Road to Mac OS X Snow Leopard: 64-bits, Santa Rosa, and the great PC swindle

[AppleInsider]

Snow Leopard's across-the-board leap to 64-bits, from the kernel to all of its bundled apps, will do more than just make more memory available. It also exposes a great PC swindle and highlights Apple's lead in 64-bit computing. Here's why.

Following the initial introduction to 64-bit computing leading up to Snow Leopard, this second segment takes a look at the issues related to the amount of RAM that can be installed and actually used by the system. Additional segments will examine how much memory a specific app can reserve for itself, how the OS gets faster with 64-bit addressing despite the additional overhead involved, how the market for 64-bit apps is unfolding, and how Apple is pioneering 64-bits on the desktop.

Road to Mac OS X Snow Leopard 1: 64-bits
2: 64-bits, Santa Rosa and the great PC swindle
3: Twice the RAM, half the price, 64-bits
4: The Future of 64-bit Apps

Virtual Memory, PAE, and the 4GB barrier

Right now, few mainstream users need more than 4GB of RAM, even when running a 64-bit operating system. An OS can manage a large 64-bit virtual address space and simply page memory into the limited amount of RAM available as needed, using the hard drive as overflow when required (below left). Consumers will eventually want a full 4GB however, and many power users already need even more than that right now.

Because hardware with 32-bit addressing can only work with 4GB of RAM at once, special tricks such as Intel's PAE (Physical Address Extension) are needed to take advantage of more physical RAM (below right). PAE can give the system more breathing room in the amount of RAM it has access to, an important factor in reducing the kernel's need to page memory in and out to a relatively slow hard drive.

Mac OS X running on a new Mac Pro or Xserve can handle as much as 32GB of installed RAM using PAE. Linux can also use PAE, but 32-bit Windows PCs are stuck at a maximum of 4GB of installed RAM. Windows XP initially offered support for using more than 4GB with PAE, but this caused problems related to driver bugs, so Microsoft simply disabled support for more than 4GB, starting with Windows XP SP2 and continuing into Windows Vista. Unless you're running Vista x64 or an expensive "datacenter" or "enterprise edition," you simply can't use more than 4GB of RAM on a Windows PC.



System RAM vs MMIO: the "where is my 4GB?" problem

If you're feeling cramped within 4GB, hold on tight because things are about to get worse. The first issue is a historical limitation in the Intel x86 architecture, related to "Memory Mapped I/O." Essentially, all of the device memory used by video cards or any other expansion cards is mapped on top of the 4GB addresses used by the system's RAM. This didn't used to be a problem before anyone wanted to actually use the entire 4GB address space for system RAM.

Note that this doesn't mean that MMIO "eats up" your RAM, it's just that the hardware maps that device-related memory over the top of physical memory, leaving fewer addresses available to the operating system to use for its system RAM. This problem is tied to 32-bit chipsets, which are independent from the CPU. There are 64-bit PCs with 32-bit chipsets. For example, Apple's 64-bit Core 2 Duo laptops prior to the second half of 2007 all used 32-bit addressing.

That means that while they can execute 64-bit code and handle 64-bit virtual memory, they still can't address more than 4GB of physical RAM, minus roughly 0.75 GB of MMIO, for a grant total of 3.2GB usable RAM. If you install a full 4GB, the portion in conflict with the MMIO will simply not be used. For PC users installing a high end video card with 1GB of VRAM, the additional MMIO becomes an even greater problem: their usable system RAM shrinks by down to around 2.3GB.



The great PC RAM swindle

With Intel's "Santa Rosa" platform, Apple's Core 2 Duo machines gained chipset support to internally handle 8GB of address space. This allows Santa Rosa Macs to shove MMIO up into the high end of the space and reclaim all of the addresses below the 4GB mark, making the full amount available to the system. No version of 32-bit Windows supports this, and conversely, there is no 32-bit version of Mac OS X Leopard, so the "where is my full 4GB?" issue is now a Windows-only problem going forward.

Prior to using the Santa Rosa platform, Apple sold its laptops as only supporting a maximum of 3GB RAM because of this. However, many Original Equipment Manufacturer PC assemblers represent their machines as supporting 4GB of RAM even though the operating system can't actually make any use of a big chunk of it. With hardware that only supports 32-bit addressing, no operating system can make use of the full 4GB. However, even with Santa Rosa-style hardware that can make use of the full 4GB, the mainstream 32-bit Windows Vista still won't use more than 3.2GB or less because it can't remap MMIO.

One developer we consulted about the issue noted, "consumers are being scammed by [PC] OEMs on a large scale. OEMs will encourage customers to upgrade a 2GB machine to 4GB, even though the usable RAM might be limited to 2.3GB. This is especially a problem on high-end gaming machines that have huge graphics cards as well as lots of RAM."

"Microsoft even changed the way the OS reports the amount of RAM available; rumor is, due to pressure from OEMs," the developer told us. "In Vista and prior, it reported usable RAM, while in SP1 they changed it to report installed RAM ignoring the fact that much of the RAM was unusable due to overlap with video memory." And so many PC users are installing 4GB of RAM in their PCs and thinking that it is being used by the system, when in fact it is no more beneficial than if the RAM were simply poked halfway into the CD slot.

For example, Dell's top of the line $5799 Alienware gamer PC comes standard with a 1GB video card, 2GB of RAM, and 32-bit Windows Home Premium. That means the system can only possibly use 2.3GB of RAM, but Dell "recommends" users spend $250 (or $8 per month with financing) to buy a 4GB upgrade (below) that will offer them little more than bragging rights, as the 1GB video card and the roughly 750MB of other MMIO will make the extra 2GB unusable. Dell says "Upgrading your memory allows you to take full advantage of system capabilities as well as increasing system efficiency," but that's simply not true on this page.



The next segment will look at another aspect of RAM use in Mac OS X that underlines why apps can use more memory than apps in Windows Vista, and how this relates to performance gains coming in Snow Leopard.

[ View this article at AppleInsider.com ]

[crees!]

Nothing like a good read at 7AM. Thanks Dan.

[merdhead]

So Windows is screwed up? What a revelation!

[digitalclips]

Originally Posted by merdhead

So Windows is screwed up? What a revelation!

Not only screwed up but screwed their customer base. I hope Apple starts making this well known out there in PC Fan Boy Land.

"Hi I'm a Mac. Excuse me PC, how much memory did you pay for and how much do you really have?"

"Hi Mac, mmmm ... I can't remember, I must have a memory problem ..."

[Pascal007]

Originally Posted by digitalclips

Not only screwed up but screwed their customer base. I hope Apple starts making this well known out there in PC Fan Boy Land.

"Hi I'm a Mac. Excuse me PC, how much memory did you pay for and how much do you really have?"

"Hi Mac, mmmm ... I can't remember, I must have a memory problem ..."

Nice !

Unfortunately, for some people, it will be a revelation to read that Windows is screwed up !

[fuyutsuki]

Originally Posted by AppleInsider

No version of 32-bit Windows supports this, and conversely, there is no 32-bit version of Mac OS X Leopard, so the "where is my full 4GB?" issue is now a Windows-only problem going forward.

[ View this article at AppleInsider.com ]

Careful how you word it Daniel. I know you mean "when using 64 bit hardware, there is no '32 bit version' of Leopard", but I happen to be running Leopard in 32 bits right here on my old G4.

[ascii]

Not all video cards take address space away from main memory do they? Some are communicated with via the PCI bus.

[cnocbui]

for a grant total of 3.2GB

grand total.

Great article.

[Bageljoey]

Originally Posted by AppleInsider

And so many PC users are installing 4GB of RAM in their PCs and thinking that it is being used by the system, when in fact it is no more beneficial than if the RAM were simply poked halfway into the CD slot.

I know people complain about the partisan comments in these technical articles, but you gotta love this image...

[thor79]

Yeah...PC users are getting screwed over if they stay uninformed. If they choose to become informed even the most basic research will deliver the correct answer, upgrade to a 64 bit OS. Since all recent essential hardware supports 64 bit just throwing on a 64 bit OS is all that is needed to solve the problem.

PC Fan Boy Land.

PC Fan Boys such as me already know of the issue...this is nothing new. This only affects non-techies who know crap about their computer. These are the same people who take their computer troubles to the Geek Squad and get screwed over there...losing documents unnecessarily and buying unnecessary hardware when their current hardware is fine. These are the same people who, when they get fed up with their PC, switch to Mac after some salesman tells them Macs run flawlessly, which is another lie.

[solipsism]

Originally Posted by thor79

Yeah...PC users are getting screwed over if they stay uninformed. If they choose to become informed even the most basic research will deliver the correct answer, upgrade to a 64 bit OS. Since all recent essential hardware supports 64 bit just throwing on a 64 bit OS is all that is needed to solve the problem.

PC Fan Boys such as me already know of the issue...this is nothing new. This only affects non-techies who know crap about their computer. These are the same people who take their computer troubles to the Geek Squad and get screwed over there...losing documents unnecessarily and buying unnecessary hardware when their current hardware is fine. These are the same people who, when they get fed up with their PC, switch to Mac after some salesman tells them Macs run flawlessly, which is another lie.

You do have some good points in regard to hyperbolic absolute statements, however: Most people are not technical with computers and shouldn't be expected to be; while Macs don't run flawlessly the more seamless HW/SW integration and included SW makes for an easier system for these non-technical masses to use; & there has been long term, well known, rampant 64-bit driver support issues with Windows.

[thor79]

Originally Posted by solipsism

You do have some good points, however: Most people are not technical with computers and shouldn't be expected to be, there is has been long term, well known rampant 64-bit driver support issues with Windows, and while Macs don't run flawlessly the more seamless HW/SW integration and included SW makes for an easier system for these non-technical masses to use.

I will give you that...you combine hardware from 5 different manufacturers with an OS from yet another company...you're bound to have problems a lot of the time. Where you see issues for the non-tech masses I see unnecessary restrictions placed on hardware and software that is operating in Macs. Apple keeps a stranglehold on their hardware and software...this much I know. I have a taste of it through owning my iPhone 3G (the only reason I came to this site, since it's the only Apple product I own). Personally I would much rather have a more open market and figure it out for myself. That's just me though.

There is a lot that needs fixing on both sides of the fence...more on the PC side than Macs for the non-tech crowd though. If PC makers and PC tech Shops like the Geek Squad (ok I guess they probably do Macs as well, seeing how BB sells Macs) would be a hell of a lot more honest with their customers Apple probably wouldn't be seeing the switch rate that they are. Honestly...I hope Apple can put some pressure on PC Makers and Microsoft to make them straighten up and fly right.

[solipsism]

Originally Posted by thor79

Personally I would much rather have a more open market and figure it out for myself. That's just me though.

And because of the free market system you can do just that. You can choose to run the OS on the HW you want. Regarding your iPhone, for a technical person the constrictions may seem severe, but you can always jailbreak it if you wish, but more importantly you should see what the iPhone is doing for the smartphone market as a whole. Nolia/Symbian, BB, WinMo aficionados are benefiting from Apple's move into the smartphone market. The same thing has happened with Macs and PCs in the past: the specialized boutique systems paving the way for the masses in a less confined space.

If PC makers and PC tech Shops like the Geek Squad (ok I guess they probably do Macs as well, seeing how BB sells Macs) would be a hell of a lot more honest with their customers Apple probably wouldn't be seeing the switch rate that they are.

I think people are just fed up in general with Windows. The universal system of the internet, the fact that you can put Windows on your Mac in various ways if need be, the integration of their popular iPod, and the proliferation of Apple stores has given people a chance to see a Mac outside of a school lab. PC tech shops, like any repair place (read: auto repair) has always has a reputation for taking advantage of the ignorant customer. Such is life, that isn't going to change.

BTW, I did call recently and Geek Squad does service Macs now.

[just_a_guy]

so apparently the 2 gb of memory on my mbp ends up being more useful by default due to the requirements of the mac os vs the PeeCee os, and the peecee users cannot really upgrade their memory to something really usefull anyway.... gee microsoft now you wonder why your OS is so sloooooow!

[minderbinder]

Unless you're running Vista x64 or an expensive "datacenter" or "enterprise edition," you simply can't use more than 4GB of RAM on a Windows PC.

That's wrong. There's also XP64 which can use as much ram as a mac (actually more in most cases since there are so many more 64 bit windows apps).

I guess there are probably some windows users who have more ram installed than the system can handle, but there are also plenty of PC users running the 64 bit version of either XP or Vista and using every bit of their ram.

This article is REALLY misleading, it spins things like mac users can use all the ram while PC users can't when in fact PC users can use it all with a 64 bit OS, and there are way more 64 bit apps on the PC side.

[Messiah]

That's a very informative article – many thanks for that!

[Booga]

That's wrong. There's also XP64 which can use as much ram as a mac (actually more in most cases since there are so many more 64 bit windows apps).

I guess there are probably some windows users who have more ram installed than the system can handle, but there are also plenty of PC users running the 64 bit version of either XP or Vista and using every bit of their ram.

This article is REALLY misleading, it spins things like mac users can use all the ram while PC users can't when in fact PC users can use it all with a 64 bit OS, and there are way more 64 bit apps on the PC side.

This is a good point if worded a little inflammatorily... XP and Vista both have 64 bit editions, and the percentage of users buying the 64-bit editions has made huge jumps in the last few months. Some OEMs are even making the 64-bit editions of Windows the default on all new desktops. At this point I suspect the market share of 64-bit Windows is at least as big as the total MacOS market share.

And because Microsoft didn't make the bone-headed decision not to support 64-bits on their older APIs, users will actually be able to *USE* 64 bits on their software, unlike Mac Photoshop users for example.

All in all, Apple blew the 64 bit transition big-time. They had a much better story than Windows a year ago but now are way behind.

[kerryb]

Not a geek but not clueless either, my 2008 Mac Pro will benefit by using 8 gigs or ram or not? Anyone?

[hankvaccaro]

Did I hear anyone say "Class Action Lawsuit - False Advertising" please?? Or at least can we have a new John Hodgman PC Guy commercial on this? Maybe with the cheerleaders chanting "2, 4, 6, 8 how much ram can Vista rate? Class Action, Class Action, come on team win that suit!!"

[backtomac]

Originally Posted by kerryb

Not a geek but not clueless either, my 2008 Mac Pro will benefit by using 8 gigs or ram or not? Anyone?

Yes it will benefit. It uses PAE.

[zmonster]

Honestly, the only 'swindle' here is that when you run a 64-bit app, it takes up roughly 2x the memory that the same app does under 32-bit. The reason 64-bit architectures address more memory is because they NEED more memory. Therin lies the problem! Yes, 64 bit apps MAY run faster, but you're going to need a machine with 2x the memory you currently have in your 32-bit machine JUST to break even (and you'll probably need 4x to see a big difference in performance). So that's the good news and bad news all in one.

[HipPriest]

This article is full of misinformation, propaganda, and errors of omission. Apple is hardly an example of a good transition to a 64-bit OS. Their marketing has claimed they are 64-bit, but not really, until 10.6 (maybe). I can't even deduce any real technical details from their marketing hype.

Let's review the issues to try to get some clarity:

Hardware: Intel's 32-bit chips had an extension called PAE, that was a hack to support more than 4GB of RAM, but not "directly". At this point, it is best forgotten. AMD released their 64-bit Opteron chips that support 64-bit addressing and MMIO. Intel copied the AMD 64-bit IS extensions but did not have the integrated memory controller, and hence had a limitation that expansion cards had to be mapped under 4GB, potentially conflicting with real RAM. This is an Intel chipset limitation, and has nothing to do with the AMD64 instruction set that both use, or Apple, Microsoft, or Linux OS.

Software: Both Linux and Windows have 32 and 64-bit versions available, meaning the full stack, kernel, drivers, and applications. Again, if you have an Intel chip, you might not be able to use all your RAM, but this has nothing to do with the OS. For years you've been able to install 64-bit Linux on an AMD Opteron and not have to worry about any of this nonsense.

As for Apple, it would be nice if an article on a site such as AppleInsider could explain what they currently have, and what they are planning, because I still don't understand it. But that is not this biased article.

[zmonster]

Originally Posted by Booga

All in all, Apple blew the 64 bit transition big-time. They had a much better story than Windows a year ago but now are way behind.

No they didn't. Apple is smart enough to know that 64-bit apps take up 2x the memory that the same app running under 32-bit does. Customers would have stormed the gates if they were forced into 64-bit, thereby requiring them to double the amount of RAM in their systems at their own cost (or otherwise see performance DECREASES).

I don't see the benefit of going to 64-bit for most people. Trust me, when this hits, people are going to complain. They'll need 16 GB of memory when they thought 8GB would be more than enough. That extra $300 is going to piss people off.

[dr_lha]

Originally Posted by HipPriest

Software: Both Linux and Windows have 32 and 64-bit versions available, meaning the full stack, kernel, drivers, and applications. Again, if you have an Intel chip, you might not be able to use all your RAM, but this has nothing to do with the OS. For years you've been able to install 64-bit Linux on an AMD Opteron and not have to worry about any of this nonsense.

This may be true to a hardcore Linux user, but let me tell you, at work one of our guys recently got a new Linux box with 64 bit linux installed, and non of the software we used worked on it. Getting the box to a point where it could actually run 32bit linux apps was by no means trivial, and in the end we just decided to install 32bit Debian on it as the easiest answer. So please don't make out that 64 bit linux is completely trivial compared to Mac OS X.

As for 64 bit Windows don't make me laugh, there's a reason why nobody uses it.

Macs have had by far the smoothest transistion to 64 bit. I've been running 64 bit apps on my Mac since Tiger came out. The only ball that Apple have dropped was not delivering 64 bit Carbon.

Apple's one OS strategy for 32bit/64bit CPUs compared to Windows and Linux separate versions is the far superior strategy both for compatibilty and user experience. I speak as someone who works in a 3 OS environment, where we have 64 bit capable chips, but due to the issues with Linux and Windows, only the Macs we have are actually capable of running 64 bit apps.

[buststyles]

Originally Posted by HipPriest

This article is full of misinformation, propaganda, and errors of omission. Apple is hardly an example of a good transition to a 64-bit OS. Their marketing has claimed they are 64-bit, but not really, until 10.6 (maybe). I can't even deduce any real technical details from their marketing hype.

Let's review the issues to try to get some clarity:

Hardware: Intel's 32-bit chips had an extension called PAE, that was a hack to support more than 4GB of RAM, but not "directly". At this point, it is best forgotten. AMD released their 64-bit Opteron chips that support 64-bit addressing and MMIO. Intel copied the AMD 64-bit IS extensions but did not have the integrated memory controller, and hence had a limitation that expansion cards had to be mapped under 4GB, potentially conflicting with real RAM. This is an Intel chipset limitation, and has nothing to do with the AMD64 instruction set that both use, or Apple, Microsoft, or Linux OS.

Software: Both Linux and Windows have 32 and 64-bit versions available, meaning the full stack, kernel, drivers, and applications. Again, if you have an Intel chip, you might not be able to use all your RAM, but this has nothing to do with the OS. For years you've been able to install 64-bit Linux on an AMD Opteron and not have to worry about any of this nonsense.

As for Apple, it would be nice if an article on a site such as AppleInsider could explain what they currently have, and what they are planning, because I still don't understand it. But that is not this biased article.

The article states that there are a 64 bit versions of windows. The writer is highlighting the fact that PC vendors market and sell machines that a regular 32 bit addition of windows is installed on and charge you more for basically useless ram.

Also he article did not attempt to make a comparison with linux or other chip manufactures.

[Sabon]

Originally Posted by zmonster

Honestly, the only 'swindle' here is that when you run a 64-bit app, it takes up roughly 2x the memory that the same app does under 32-bit. The reason 64-bit architectures address more memory is because they NEED more memory. Therin lies the problem! Yes, 64 bit apps MAY run faster, but you're going to need a machine with 2x the memory you currently have in your 32-bit machine JUST to break even (and you'll probably need 4x to see a big difference in performance). So that's the good news and bad news all in one.

I have no idea where you get your ideas but this is NOT fact. 64 bit apps do NOT automatically take up twice the memory. It CAN but most do not. If this were true then there would be no reason to get 64 bit apps.

To actually have a clue. Go back and look at 16 bit vs 32 bit apps and stop spewing false information.

[Prince]

Originally Posted by thor79

Yeah...PC users are getting screwed over if they stay uninformed. If they choose to become informed even the most basic research will deliver the correct answer, upgrade to a 64 bit OS. Since all recent essential hardware supports 64 bit just throwing on a 64 bit OS is all that is needed to solve the problem.

No, PC users are getting screwed over if they try to buy a PC and Dell tells them to spend money on an upgrade they can't use, and Windows Vista tells them the memory is "installed" rather than pointing out that it can't use it. That's a lie on both sides of PC land.

Apple's systems that can't support more than 3GB are listed as only supporting 3GB, and can't be configured with more RAM than that. Apple is being honest, and Dell and Microsoft aren't.

PC Fan Boys such as me already know of the issue.

Few understand this, and nobody should have to out-think the false advertising of their vendor. When Windows Enthusiasts complain about "Get a Mac" ads being deceptive because they are emotionally upset by them (that's not what 'deceptive' means by the way) and then turn around and make excuses for PC makers and Microsoft simply lying to them to steal their money, it only shows how irrational they are.

[HipPriest]

Originally Posted by dr_lha

This may be true to a hardcore Linux user, but let me tell you, at work one of our guys recently got a new Linux box with 64 bit linux installed, and non of the software we used worked on it. Getting the box to a point where it could actually run 32bit linux apps was by no means trivial, and in the end we just decided to install 32bit Debian on it as the easiest answer. So please don't make out that 64 bit linux is completely trivial compared to Mac OS X.

As for 64 bit Windows don't make me laugh, there's a reason why nobody uses it.

Macs have had by far the smoothest transistion to 64 bit. I've been running 64 bit apps on my Mac since Tiger came out. The only ball that Apple have dropped was not delivering 64 bit Carbon.

Apple's one OS strategy for 32bit/64bit CPUs compared to Windows and Linux separate versions is the far superior strategy both for compatibilty and user experience. I speak as someone who works in a 3 OS environment, where we have 64 bit capable chips, but due to the issues with Linux and Windows, only the Macs we have are actually capable of running 64 bit apps.

What 32-bit Linux apps did you have trouble running? We run an all 64-bit Debian Linux environment at work on hundreds of systems and my experience has been much better than yours. 64-bit Debian has packages for the most common 32-bit libraries used by third-parties and of course most Linux software is open source and 64-bit native. The only thing 32-bit we run is shake, which runs fine, and the flash plugin, which needs a wrapper, and runs as well as... flash usually runs.

As for the Mac, could you explain (or point me to an article) the technical details for Apple's 64-bit approach, from a kernel, driver, library (API) and application level. That was my frustration with Apple's marketing double-speak ("We are 64-bit! But wait, with Snow Leopard we are _really_ 64-bit!") and with the articles on this site. I'd like more details and less hype.

[guinness]

Originally Posted by dr_lha

This may be true to a hardcore Linux user, but let me tell you, at work one of our guys recently got a new Linux box with 64 bit linux installed, and non of the software we used worked on it. Getting the box to a point where it could actually run 32bit linux apps was by no means trivial, and in the end we just decided to install 32bit Debian on it as the easiest answer. So please don't make out that 64 bit linux is completely trivial compared to Mac OS X.

As for 64 bit Windows don't make me laugh, there's a reason why nobody uses it.

Macs have had by far the smoothest transistion to 64 bit. I've been running 64 bit apps on my Mac since Tiger came out. The only ball that Apple have dropped was not delivering 64 bit Carbon.

Apple's one OS strategy for 32bit/64bit CPUs compared to Windows and Linux separate versions is the far superior strategy both for compatibilty and user experience. I speak as someone who works in a 3 OS environment, where we have 64 bit capable chips, but due to the issues with Linux and Windows, only the Macs we have are actually capable of running 64 bit apps.

Leopard still has a 32-bit kernel, it can run 64-bit apps, and address more than 4 GB, but it's not fully 64-bit. Whether you're running Leopard now, or a 32-bit version of Windows, you're still going to have to upgrade if you want a true 64-bit OS. If that wasn't the case, their would be no need for SL.

Most PCs I've seen sold with 4 GB are coming with Vista x64 ATM, they're stopping at 3 GB if their coming with 32-bit. Or some older computers could run a 64-bit OS, but run into memory limitations, because of the chipset like my current C2D Mini. I could put 4 GB into it, but it would only show up as ~3.3 GB because of it's craptastic Intel chipset. I have no such problem with my AMD systems however.

I've run into that issue with Linux x64 with installing apps too, and I didn't like forcing 32-bit apps to run. As far as Windows, I've only dealt with XP x64 and never liked that due to driver issues, but most things I have read regarding Vista x64 is that there aren't many issues, and those that have been running Lightroom 2 x64 have liked it quite a bit (thread over on dpreview.com).

[Clive At Five]

Originally Posted by minderbinder

There's also XP64 which can use as much ram as a mac (actually more in most cases since there are so many more 64 bit windows apps). [...] This article is REALLY misleading, it spins things like mac users can use all the ram while PC users can't when in fact PC users can use it all with a 64 bit OS, and there are way more 64 bit apps on the PC side.

Originally Posted by solipsism

...there has been long term, well known, rampant 64-bit driver support issues with Windows.

I'm going to have to agree with Sol on this one. I consider myself a pro-user and I still couldn't put up with 64-bit XP, though I can't speak for Vista. A pro-user friend of mine is running 64-bit Vista and loves it, but he's a Windows-only guy, so who knows?

I know I criticize Apple a lot, but I have to hand it to them: their transition to 64-bit has been seamless. I'm really hoping Windows 7 will make it easier to switch, because there's no chance I'm going to install Vista.

-Clive

[Cubert]

Lawsuit against the OEM's for making this false RAM claim in 5, 4, 3, 2, 1.....

[zmonster]

Originally Posted by Sabon

I have no idea where you get your ideas but this is NOT fact. 64 bit apps do NOT automatically take up twice the memory. It CAN but most do not. If this were true then there would be no reason to get 64 bit apps.

To actually have a clue. Go back and look at 16 bit vs 32 bit apps and stop spewing false information.

HUH?? You are completely clueless. The Object-C object size in a 64-bit compilation is exactly 2x the size of the 32-bit data structure. The integer is 2x the size. Most every other data structure is nearly 2x the size. 64-bit apps take up ROUGHLY 2x the size that 32-bit apps do. PERIOD. You are wrong, my friend.

If you don't believe me, find a 64 bit machine, install both the 32-bit version of Java, and a 64-bit JVM. Run the same app on both. This is NOT limited to Apple, EVERY 64-bit architecture takes up nearly twice the memory that a 32-bit architecture takes up. Take a computer science class.

[wizard69]

Originally Posted by zmonster

Honestly, the only 'swindle' here is that when you run a 64-bit app, it takes up roughly 2x the memory that the same app does under 32-bit. The reason 64-bit architectures address more memory is because they NEED more memory. Therin lies the problem! Yes, 64 bit apps MAY run faster, but you're going to need a machine with 2x the memory you currently have in your 32-bit machine JUST to break even (and you'll probably need 4x to see a big difference in performance). So that's the good news and bad news all in one.

Of all the misrepresentations in this thread I do believe this is the worst. Mainly because it is in no way a universal truth. Most apps will come in larger but seldom get even close to 2x in size, many apps that benefit from a 64 bit environment see only a marginal increase in foot print. Moreso a few cases might even show a memory benefit going to 64 bit. It all depends on the code and how well it maps to the instruction set.

As to the article that started this thread let's just say it needs work! The overall tone is not to bad when comparing commonly shipped os'es but really butchers the truth getting there. Need to do better boys!


Dave

[sblackst]

Windows XP initially offered support for using more than 4GB with PAE, but this caused problems related to driver bugs, so Microsoft simply disabled support for more than 4GB, starting with Windows XP SP2 and continuing into Windows Vista. Unless you're running Vista x64 or an expensive "datacenter" or "enterprise edition," you simply can't use more than 4GB of RAM on a Windows PC.

Not quite the full story. PAE was a 'hack' for certain server-side applications on Windows and performance would be affected. I'm not surprised at all that Microsoft yanked it from XP to push their x64 initiative.

And to your other point, here's a list of Microsoft x64 operating systems:

Windows XP x64 - Home, Professional Editions
Windows Vista x64 - Home Basic, Home Premium, Business, Enterprise, Ultimate Editions
Windows Server 2003 x64 - Standard, Enterprise, Web and Datacenter Editions
Windows Server 2008 x64 - Standard, Enterprise, Web and Datacenter Editions

Rgds,

Simon

[badtruffle]

Originally Posted by zmonster

Honestly, the only 'swindle' here is that when you run a 64-bit app, it takes up roughly 2x the memory that the same app does under 32-bit. The reason 64-bit architectures address more memory is because they NEED more memory. Therin lies the problem! Yes, 64 bit apps MAY run faster, but you're going to need a machine with 2x the memory you currently have in your 32-bit machine JUST to break even (and you'll probably need 4x to see a big difference in performance). So that's the good news and bad news all in one.

This is such egregious misinformation that I had to sign up just to counter it :P

The only memory that needs to double in 64-bit programs is pointers. This is a chunk of memory that references other locations in memory for whatever reason the programmer needs. These go up from 4 bytes (32 bits) in older architectures to 8 bytes in 64-bit architectures. The default size of certain numeric can also increase depending on the programmer's knowledge of what size number he needs, but doesn't have to.

Regardless, most of a program's memory is not taken up by pointers or "numbers". Although pointers are very prevalent, the executable code (which does not change significantly for 64-bit memory) that uses them is proportionally much larger, and stays that way in 64-bit code too. Also, the single biggest memory hog, "program data" (images, large binary file formats, databases, and so on) is almost completely unaffected by the memory address size.

So yeah, none of that "needs 2x memory to keep up, and 4x to have better performance" cr*p. More memory does not equal better performance unless the program tends to load large data files or do huge data processing in memory. The advantages of 64-bit memory (not having to tiptoe around the allocator when the hardware technology is ready) address far outweigh the drawbacks.

[CDN_newguy]

Originally Posted by AppleInsider

...for a grant total of 3.2GB usable RAM. If you install a full 4GB, the portion in conflict with the MMIO will simply not be used. For PC users installing a high end video card with 1GB of VRAM, the additional MMIO becomes an even greater problem: their usable system RAM shrinks by down to around 2.3GB.

Uhhh... no. That's not correct.

Using a "high end video card" means you have frame buffer ON THE CARD, meaning you don't use system memory. If by "high end video card" you mean Intel's integrated graphics and you jack the memory allocated to this controller to 1GB, then yes - you will use an extra 1GB of system memory, but BY NO MEANS are you using a high end video card.

I'm always amazed that people blindly believe everything that is written on the web.

P.S. Not a fanboi... I'm running XP Pro x64, but I also use iTunes and an iPhone (and no, there are no x64 drivers for the iPhone, and iTunes has to be tricked into running on x64, but that's Steve-o's doing, isn't it?)

[badtruffle]

Originally Posted by CDN_newguy

Uhhh... no. That's not correct.

Using a "high end video card" means you have frame buffer ON THE CARD, meaning you don't use system memory. If by "high end video card" you mean Intel's integrated graphics and you jack the memory allocated to this controller to 1GB, then yes - you will use an extra 1GB of system memory, but BY NO MEANS are you using a high end video card.

I'm always amazed that people blindly believe everything that is written on the web.

P.S. Not a fanboi... I'm running XP Pro x64, but I also use iTunes and an iPhone (and no, there are no x64 drivers for the iPhone, and iTunes has to be tricked into running on x64, but that's Steve-o's doing, isn't it?)

the memory is on the card, but it still cuts into the addressable memory on the host system, which is what his point was.

[buststyles]

Originally Posted by CDN_newguy

Uhhh... no. That's not correct.

Using a "high end video card" means you have frame buffer ON THE CARD, meaning you don't use system memory. If by "high end video card" you mean Intel's integrated graphics and you jack the memory allocated to this controller to 1GB, then yes - you will use an extra 1GB of system memory, but BY NO MEANS are you using a high end video card.

I'm always amazed that people blindly believe everything that is written on the web.

P.S. Not a fanboi... I'm running XP Pro x64, but I also use iTunes and an iPhone (and no, there are no x64 drivers for the iPhone, and iTunes has to be tricked into running on x64, but that's Steve-o's doing, isn't it?)

The article did not say the video card uses system memory, but the a video card memory will use the memory addresses that are assigned for system memory(MMIO).
So a 1GB will take up additional address to decrease for example 3 GB of accessible ram to 2GB of accessible ram.
But since you have 64 bit XP this is not a problem for you.

[zmonster]

Originally Posted by badtruffle

This is such egregious misinformation that I had to sign up just to counter it :P

OK, you geniues know everything, and you've written test code to explore the memory requirements of the two use cases just like I have.

Go ahead and run Photoshop on your new 64 bit machines with the same amount of memory that you're running it under 32-bit. See how far that gets you.

[danami]

This story is bad. You are blaming Microsoft for not supporting PAE? Duh? They already have multiple 64bit operating systems that work just fine. The 4GB memory limit is a problem of all 32 bit OS's .. And like other people have pointed out PAE is a piece of crap.. I'm a linux server admin and work with a lot of hi-mem systems with openvz.. You always install the 64bit OS over PAE as PAE has way too much overhead.. Both 64bit and 32bit apps run fine on a 64bit OS..

Oh ya I'm writing this on my vista 64 OS with 8 gig ram .. running all my 64/32 apps and games fine .. and it supports every piece of hardware that I've ever thrown at it!