Apple adds SSD TRIM support to Mac OS X 10.7 Lion beta - Page 2

Serious question: How can you tell if your OWC does indeed have Sandforce? I bought mine a year or so ago and I don't recall reading anything about Sandforce. Looking at my Apple Profile doesn't show anything either:

OWC Mercury Extreme Pro SSD:

Capacityt120.03 GB (120,034,123,776 bytes)
ModeltOWC Mercury Extreme Pro SSD
Revisiont310A13F0
Serial NumbertMX12010E23A0806
Native Command QueuingtYes
Queue Deptht32
Removable MediatNo
Detachable DrivetNo
BSD Nametdisk0
Medium TypetSolid State
TRIM SupporttNo
Bay NametLower
Partition Map TypetGPT (GUID Partition Table)
S.M.A.R.T. statustVerified

It doesn't tell me that at all. It tells me that Apple got wise and instead of requiring the laborious process of booting of DVD to then repair they wisely chose the multi-bootloader approach to save the consumer/admin a large amount of time to fix the systems.

Imagine having automated scripts to routinely monitor thousands of deployed systems and then for each one that fails to respond accordingly you send a remote reboot and then automagically check the repair boot up and fix it remotely.

It sure beats the hell out of physically got to each and every machine.

@ toyin: right on the mark.

I have a 2009 Mini and I bought an OWC 128 GB Mercury about a year ago. I took the existing drive and mounted it in a special carrier and stuck it where the optical drive was housed. I use the original HDD as the primary backup on one partition, and have lots of lesser-used files (like 80GB of songs) on another partition. The OWC is currently about half full: All the necessary System and Application files, my Pictures and Documents folders (which I keep trimmed as needed).

One app that I find extremely useful in trimming things down is Whatsize, which tells me when some folders need to be trimmed or discarded.

Oh, that optical drive? The outfit that sold me the HDD carrier kindly provided a USB case for it. It's tucked out of sight until I need it (one a week or less!)

Can't say much more, but that information is old, very old.

Whoever said that was doing it wrong

SSD's are NOTICEABLY faster - my Mac Pro with my OWC SandForce based SSD boots in about 4 seconds, vs. almost 30 with the stock hard drive.

Aperture - dont' even get me started on Aperture! Since I put the Aperture library on my SSD and reference the masters on my internal RAID array, I never wait for Aperture. Before when Aperture would slow to an absolute crawl due to it's database files getting fragmented I would have to stop, launch iDefrag and go for a walk while it did it's thing. Now if the Aperture database files fragment it doesn't mater since unlike hard drives that have to physically move a head to read different parts of a disk an SSD can just retrieve the required information without latency. In other words reads never slow down, no matter how fragmented or scattered data is on the disk - it's blistering fast all the time!

That's the huge and the incredible benefit of SSD's.

Where people get into problems with SSD performance, and where the article really massacred the explanation, is in write speed. Flash memory is comprised of "Cells" and they are pretty big in size - certainly larger than the individual bits on a magnetic hard drive. And if you have a partially filled cell, before you can write anything to it, the whole cell has to be erased - then the old data and the new data is written back. That's pretty slow - and it can make an SSD feel slower than a floppy.

To combat this, SSD drives do a "defragment" - but instead of defragmenting files, they defragment partially filled cells to ensure there is a healthy supply of completely empty cells that are pre-erased and waiting to be written to at maximum speed.

There are two ways around it - TRIM basically let's the OS communicate with the drive at a low level and tell the drive what data is "real" and what data has been deleted. This allows the SSD controller to shuffle and consolidate partially full flash memory cells and create empty cells to ensure maximum write performance.

The second way, which is what the SandForce drives like those from OWC do, is by oversubscription - they have extra capacity - 10% to 20% - which ensures the SSD controller always has enough room to do the consolidation of partially full flash memory cells - irrespective of what the OS is doing with the drive.

The downside? Oversubscribed drives, since they have more flash memory in them and flash is expensive cost more.

The upside? SandForce drives work with ANY OS, and since they have extra capacity, as cells wear out the drive may slow a bit since it won't have as much free space and a drive might not be able to ensure there are as many empty flash cells hanging around to be written to at top speed, but the drive will last longer.

TRIM is a hack to basically allow the drives to shuffle data around without having to add extra capacity. Personally, even if Apple adds TRIM support I will still buy SandForce type drives just because they will last longer, and if there is a way I will turn TRIM off. As expensive as SSD's are, an extra 10% up front seems far more prudent to me.


For most people the rewrite cycle thing is dramatically overblown, and even the non-sandforce drives have a little extra capacity (much like modern hard drives) to handle the occasionally bad cell automatically and in the background. All SSDs also perform "wear leveling" - that is, they will move data from cells that haven't changed to cells that have had excessive changes to ensure that all cells are used equally.


On drives that don't use TRIM (like the SandForce drives) you can certainly retrieve deleted files since they don't overwrite the "unused" areas of the active drive space that is made available to the computer. All bits for the space presented to the computer are preserved at all times, just like on a traditional magnetic hard drive. You are correct that on drives that support and use TRIM you won't be able to recover files since they let the hard drive overwrite the data that has been "deleted" in the OS. You loose the ability to recover deleted files since they literally no longer exist in the traditional "neither world" of deleted but not overwritten.

Another plus for the SandForce non-TRIM drives

Remember, without TRIM, as far as the drive is concerned, the entire drive - the "useable space" it presents to the computer for use, is "good" and must be protected. Hard drives are totally ignorant of concepts such as partitions, files, "free space" from files that have been "deleted" - that's at a much higher level and why, drives that don't have extra capacity to allow for optimization, must have something like TRIM to allow the OS to tell the drive what is safe to overwrite and what must be preserved. And that's why Non-Sandforce drives eventually slow to a crawl under Mac OSX. Thankfully Mac OSX isn't nearly as chatty to hard drives as Windows so it takes longer, but with normal SSD's they will eventually slow down (including the ones Apple ships - unfortunately)

BTW - Windows XP has the same issues since it doesn't support TRIM. Not sure if Vista does, but Windows 7 does.


Yup, but they are bloody fast and well worth it for the speed - if you get the right ones on a Mac, anyway

Memory, CPU, graphics, system busses - all of those components have been progressing in speed by leaps and bounds over the past decades - but hard drive speeds are relatively unchanged. Hard drives are the largest bottlenecks in modern PC's. The majority of the new MacBook Air's speed increases come from standardizing on SSD's and eliminating pokey hard drives - of which laptop hard drives are the slowest!


Speed, speed, speed!

No latency. Never having to worry about file fragmentation slowing you down. On software such as Aperture where fragmented files incur a DRAMATIC performance hit on slow, spinning magnetic media, SSDs will make you weep with joy. But even in "normal" operations like booting the computer, launching applications and loading files the zero latency maximum throughput of quality SSDs make computers fun again. For me anyway - I hate latency

For portable computers, because they have no moving parts, SSDs are far more resilient. They also use less power, which is great for battery life.

They don't work like normal hard drives and there are a few things you need to be aware of - the biggest is the potential for worse write performance if you get the wrong kind of SSD for your Mac. Especially on the current versions of Mac OSX with the current lack of TRIM support, if you buy a non-SandForce or SandForce-like SSD that is oversubscribed and will optimize itself even without TRIM, you will be disappointed eventually as all your totally empty flash memory cells are filled or partially written to and your write performance drops like a rock. Buy the right SSD like the OWC Mercury Extreme's and you will be a happy camper indeed!

I really need to get the kit to boot the optical drive out of my MacBook Pro and replace it with an SSD - it would more than double the overall performance of the machine, and I could still keep my 500GB drive for my photo and iTunes files. The last time I used the DVD was to install SL - and I can do that over the network from the optical drive in my Mac Pro now. For me the optical drive is about as useful as a floppy

OWC has only ever sold drives that won't slow down without TRIM support.

One of the best reasons to buy from a vendor that specializes in your particular platform

EDIT: The best way to tell is if it's still fast. If so, you are good. Because if it wasn't a SandForce and you had it a year or so, you would know by now!

TRIM's not a hack — it's the other way around, really. TRIM is a way for the OS to tell the SSD controller which blocks are free and able to be erased. You see, a drive has no way to tell the difference between a block that has valuable data on it and a block that used to have data on it which has now been trashed, because the only difference between the two is that for the trashed file, the HFS+ driver has made a change in the HFS+ catalog file to remove the file's directory entry. However, at the drive level, without a knowledge of the HFS+ file format structure, both the current file and the deleted file are both just a bunch of 1s and 0s. There's no way for the SSD controller to know that those blocks are free to be erased, defragment them, or do anything else really —*it's just not possible without understanding the structure of the specific file system being used.

The way I understand it, the SandForce drives' performance comes from some weird write compression they do, compressing data on the fly to reduce the number of writes it has to do. This preserves the free blocks on the drive longer than for a normal SSD, and the large amount of extra spare blocks certainly helps as well — but you're still going to run out eventually. It'll just take longer than for other drives.

The only way the SSD controller could effectively clear out blocks that belong to deleted files would be if it has knowledge of the specific file system you're using. This may well be the case; I have no way of knowing that it's not. But I wouldn't want to use such a thing, because this type of garbage collection truly is a hack. It has a large number of problems:

- It's not OS-independent. If the SSD controller knows about NTFS but not HFS+, then the GC won't function on a Mac. If it supports both, the GC still won't function on a Linux machine using ext4.

- Even if it does support all file systems you want, then as soon as Microsoft releases WinFS, Apple releases "iFS" or something, or the Linux people come out with ext5, suddenly the GC won't function anymore without a firmware update.

- On the other hand, if Apple makes a minor improvement to HFS+ that doesn't change things drastically enough to keep it from looking like HFS+, but the SSD's GC isn't aware of this modification, it could cause all sorts of issues and incompatibilities as the GC makes assumptions about the file system format that aren't valid, possibly leading to data loss.

- And even when everything else works, you're still relying on a third-party HFS+ driver not written by Apple, which you're using to continually scan the entire drive and decide what data can be erased. God help you if the FS driver has a bug in it.

Compare all this to TRIM, where everything is far simpler; the OS's FS drivers delete a file, the OS tells the SSD which blocks are now free to be erased, and the SSD erases them. It's simple, elegant, robust, safe, and completely unlike the hack of implementing a whole file system driver on the SSD controller.

On my Air SSD I made an 8GB partition using Disk Utility (6GB would have been enough) and copied the flash software recovery drive onto it using Carbon Copy Cloner. The only complication is that the dmg file on the flash drive (which is all that you need to duplicate) is a hidden file and so I opened it in a terminal window using "ls -a" to see it and then "open mumble.dmg" (I forget what it was called) and then copied it with CCC (you can find the recovery drive in the /Volumes directory). You could also just create a small partition on the SSD and use your Snow Leopard install disk to install the OS on it.

A BIG thank you from me to you! That certainly is a very informative post.

A question, of course: I got the latest MacPro last fall and only have the stock 1TB HDD. Thought about getting 3 other 1TB drives and get the Apple RAID card, mainly for speed. Current drive is quite full, but it's not filling up fast. Would like to get speed. Would you suggest getting this RAID setup or simply add a single SSD and keep the HDD for storage? Main usage is Aperture, but after getting a Nikon D7000 and shooting video as well, I'll probably buy FCP.

TIA

And if I may ask, what do you have inside your MacPro?

Cheers,
PhilBoogie

I am not sure that data compression works that well in practice. Executable and media files are hardly compressible at all. Also if you encrypt your filesystem and/or files (increasingly common in the corporate world), they look like random data, rendering data compression completely ineffective.


Agreed this type of garbage collection would be problematic for the reasons you stated (not quoted here). However, this is not the way it works.

Garbage collection in most SSD controllers involves repacking recently invalidated sectors (ones that were logically overwritten into new physical locations) so blocks can be pre-emptively erased and ready for a future write. Think of it as defragmenting at a very low level. There is no dependency on understanding the file system.

However, for this to remain effective over the long term, the firmware needs to have known empty sectors available. One way to achieve this is to use TRIM. The other way, is to have over-provisioning or "extra capacity" on the drive, as explained by DocNo42. Spare blocks are used to write new data, with the old sectors getting invalidated and eventually cleaned up with garbage collection. Since there are always spare blocks available, write performance does not degrade. Current SandForce-based OWC SSDs have 7% or 28% over-provisioning, depending on the model.

What most people don't realise is that you can effectively achieve the same thing with other controllers by leaving some space unpartitioned on your drive. (Not to say that this makes all controllers equal by any means.)

tzb

Okay, I'm not completely crazy. It appears that I did do some research before purchasing the Crucial drive.

Crucial uses Marvell instead of Sandforce as the drives controller. You can read more about it online but here are two interesting reads

http://www.bit-tech.net/hardware/sto...buyers-guide/5

http://www.behardware.com/articles/7...-compared.html

I decided to go with the Crucial for a few reasons:
1. The 256 was on sale for $430 when I got it.
2. I assumed that OSX would support TRIM in the not too distant future.
3. The Marvell controller has SATA 6 Gbits support, which will be available in my next MBP. Call it wishful future proofing even though I'll probably upgrade to the next generation of SSD based on 25nm flash before this one dies.

Which you don't need to do if you have extra capacity.

Extra capacity costs more. Flash is expensive. To avoid having to bundle in extra capacity, TRIM was invented.

Well, and some of it was face-saving for Intel getting caught with the their pants down. By emphasizing TRIM, they didn't have to admit their early SSDs (which I have one of, thank you!) were basically flawed.

You can defragment cells and ensure totally free one's one of two ways. You can oversubscribe the drive by having more flash than you present as usable space, or you can use a hack like TRIM to shuffle flash cells within the flash that you present as useable space.

Either way you ensure the SSD has enough cells to allow the controller to shuffle things around to ensure a steady supply of totally empty and ready to write to cells.

That's it. All the other crap is smoke/mirrors, marketing fluff and people making it harder than it has to be.

If you run out of totally empty cells, your write performance drops to total crap - that's the nature and only real drawback of SSDs.


No duh. But because my SSD has about 20% more flash in the drive than is presented to the computer for use (it's over-subscribed) there is always room without the SSD having to know what is going on in the file system for the SSD controller to do it's thing to ensure there is a steady supply of totally empty flash cells to write to.

No TRIM needed. No TRIM wanted, really. And because my SSD has that extra capacity, as flash cells wear out and are flagged as unusable, my drive will still be working long after yours just dies on you. That's worth a slight premium to me.


The compression is for some performance optimization, but the primary feature that allows SandForce drives to maintain performance without TRIM is the extra flash capacity that is reserved for the SSD controller to have room to do it's thing. The compression and the extra "hidden" space serve different purposes.


Or the other way is if there is extra flash capacity that is reserved for the drives's internal use that isn't exposed to the host OS. "working space", "scratch pad" - whatever you want to call it, it serves the same purpose as drives that don't have the extra space but support TRIM - it allows the controller to optimized and ensure a steady supply of totally free cells.


All SSD's do "garbage collection". If they didn't, you would run out of totally free cells and once every cell in your SSD has data, to write new data the cell has to be read, erased and then rewritten with the old/new data.

Whether you ensure space for the SSD controller to do this "garbage collection" (I prefer optimization but whatever floats your boat) via TRIM or having extra built in reserve capacity, the basic mechanism and result is the same.

Personally I prefer the drive just take care of it - what if TRIM has a bug and tells the SSD to whack data that is really good? Seems like a solution that introduces complexity - a whole new protocol, now there is interaction between the OS, the controller and the SSD?

Meh - I'll stick with drives that have extra capacity and the SSD controller takes care of optimizing for performance without any dependency on the host OS, thank you.


You have no idea what you are talking about.


Your describing the downfall of TRIM, not over subscription. Oversubscription happens within the firmware. It's automatic. No reliance on support of a hokey protocol that's only baked into the newest OS's.


Again, the drive cares not as to what bits are on it. It's block level storage. TRIM is what is trying to give the drive visibility into what is going on at the file system and TRIM again has all of the issues you are citing.

Drives that have extra capacity to allow the controller guaranteed free space at all times to optimize themselves will work literally with any OS and any file system because, unlike drives that rely on TRIM support to ensure the SSD controller has some space to optimize with, drives with extra capacity ALWAYS have free space irrespective of what is loaded on them.


Again, irrelevant since the drive is a block level device and couldn't care less about what is on it. Every bit is sacred. This is yet another disadvantage for TRIM.


Sigh - there is no driver. The drive doesn't care!

The drive IN MY MAC PRO RIGHT NOW cares not about what is on it. It does it's thing and optimizes itself with no problem. I could format it, put Linux on it and it wouldn't slow down. I could format it, load DOS from 1989 with WIndows 3.1 and it wouldn't slow down.


HAHAHAHA - again, you have it exactly backwards. TRIM is adding a layer of complexity and introducing layered dependancies on OS and filesystem and SSD controllers all working correctly and not screwing up from bugs or anything else.

You can keep your drive with TRIM if you like - but again TRIM is a hack to allow SSD manufacturers to ensure there is space for the SSD controller to optimize within the useable space on the SSD. It's done for cost reasons - nothing else. The difference between a good OWC SSD and the cheaper SSD's that aren't oversubscribed isn't worth it - to me anyway.

And again, I think Intel is pushing TRIM to save face. They stonewalled for MONTHS on their original SSD's blaming everything from us users to sunspots before they finally had to admit that SSD's were different and that there was a problem after all It wasn't pretty.

Why else would they push something that makes the overall environment more complex with a marginal cost savings - I mean they manufacture their own flash and already charge a premium compared to others - you would think it would be more appealing to them release drives that would, gee - I don't know, work with anything loaded on them?

Things that make you go hmm....

Your welcome. I had one of the original Intel 80GB SSD's for my work laptop soon after they came out. The first three months were great - then it ground to a halt. Then I watched the fun as the finger pointing began. Then, I forget who - Anandtech? - pointed out the difference between flash and magnetic media. In a traditional hard drive writing a bit is as fast as reading. But with flash - once an empt cell is written to, to write to it again it has to be erased first. Kind of like a CDRW (the article did get that analogy right). So, not only do you have to erase the cell and then write to it, but you need to read out whatever is in there first that you want to keep. Just erasing it would be kind of bad. All of that is much, much slower than just writing to a cell that's empty.

So hence the miracle savior, TRIM appears. Thankfully some others figured out there is more than one way to skin a cat.

There is so much misconception and over-complication of the issue, I don't mind posting about it. The problem - and solutions - aren't really that hard. Most folks just have a hard time visualizing it since SSDs are fundamentally different than magnetic disk we are used to.


Skip the Apple RAID card. Nothing but pain. Just search the Mac Pro support forum at apple.com


Welp, I picked up three 750GB WD Caviar Black drives for $60 a pop on sale and have them in a software RAID 0 I created with Disk Utility. Without having to calculate parity, there's not much advantage to hardware RAID 0.

All backed up with Time Machine on a Drobo and also via BackBlaze.com mind you. I want the speed of RAID 0 but I'm not stupid Loosing one drive in a RAID 0 and the whole array goes by-by.

I also have a 500GB drive - the one my Mac Pro came with - with Windows 7 on it for dual booting. That covers the four SATA slots with the removable holders in the Mac Pro.

I have an OWC Mercury Extreme, 120 GB, in the second optical bay - that's my boot drive.

It works like a champ. With Aperture the biggest thing you can do is put your Aperture libraries on the SSD and reference the masters on magnetic disk. Unless you have unlimited funds and can put everything on SSD Luckily with Aperture 3 management of referenced masters is greatly improved and actually not a PITA as in the past.

When I installed final cut, I did a custom install and had it put all the media and other files on the RAID array instead of filling my SSD boot drive.

If you still have space on your 1TB drive, start with the SSD. Don't bother getting a holder to mount it in one of the four hard drive trays - it's not worth it. Just put the SSD in the second optical bay if it's empty. The SSD port is just as fast as the four with the removable trays. If you need more space for video or expanded photography, the 1TB WD Caviar black drives are getting dirt cheap and the software RAID 0 works well. Just back it up! BackBlaze is great - $50 a year and it will back up external drives too (unlike @^$! carbonite). You can get the USB only Drobo's cheap on special or from eBay and they are perfect for Time Machine. Throw in a couple of $80 2TB drives and off you go.

If you need more than three our four terabytes, and if I ever get to that point, I'm going to pick up a Drobo Pro. Eight slots, expandable at will, excellent support and iSCSI for fast throughput. Can do one HD stream for sure, with eight drives to spread the load across, might get two streams. I thought I had a post from another forum bookmarked where someone confirmed that but I can't find the bookmark now? Oh well...

Nope, it doesn't work that way. The hard drive is a block level device. Just as it's ignorant about file systems, it's ignorant about partitions. All you have done is deprive yourself of some very expensive flash you paid a premium for

If the drive and OS supports TRIM, you don't need to do that. If they don't, it doesn't help you anyway.

Like I said, I'll stick to over-subscribed drives for maximum flexibility and longer effective life.

Damn it all. . .

10.7 beta installed with an Intel Gen2 SSD (latest firmware) and I get TRIM Support: No. The SSD supports TRIM with other OS's even prior to the 2011 firmware I just put on.

Will keep ya posted but it's a serious disappointment if Apple only supports TRIM on their stock (read crappy) performing BTO SSDs.

I am all geared up to buy a new MacBook pro. I'm still running a 12" PowerBook so I cannot wait! Only real dilemma is between disappointing 13" graphics and portability vs 15" performance.

Anyway, my real question is, would it be a bad idea to install an SSD right now unless I get one with Sandforce? I'm really interested in the optibay route especially as it shouldn't compromise AppleCare. But it looks like without TRIM there is real risk of performance degradation really quite quickly? I have to say that Apple is really conning the non-tech community who buy into the Airs for there superfast SSDs without realising that things will
go downhill pretty quickly.

I am completely convinced by the performance boost of SSD but don't want to
invest a big chunk of money in something that isn't going to
live up to expectation for very long.

On a side note, am I right in thinking that with average use a SSD is good for at least five years?

Yes!


Unless removing the optical drive caused the problem, they can not legally deny you on warranty work. Same as if you change the memory or hard drive. Having said that, it might be easiest to put the optical drive back in before taking it in for warranty work if you need to.


Not if you buy the right drive


Apple's SSD's use a toshiba controller and so far I haven't seen anyone complain about a slow down with them - so perhaps they are oversubscribed as well. TRIM isn't required to maintain performance in an SSD. Indeed, I couldn't care less about TRIM as I greatly prefer drives that are able to optimize themselves and maintain peak performance without TRIM.


I don't blame you. I was very disappointed when my 80GB Intel SSD ground to a halt about three months after I put it in.

If you stick with the SSD's from Other World Computing (macsales.com) you won't have any issues. I've had my Mercury Extreme 120GB for over 8 months and it's just as fast as when I installed it!


Depends on how much you write to it, and it depends on the SSD - but I think for most people five years is probably more than reasonable. The more "spare" flash an SSD has, the longer it will live which is why I don't mind paying a slight premium for the SandForce based SSDs. Also, if you put write intensive stuff like Adobe Photoshop Scratch Disks on an SSD, that will cause it to "wear" faster as well.

Personally I'm not going to worry about it. Even if I had to replace them ever two years, the performance difference with SSD vs. HD is substantial enough it is more than worth it.

I did read about &^$@# RAID card over at Apple's forum. Sometime ago, but probably the reason why I asked you...so thank you for replying. Again with more useful info.


After reading your advise, I think I'll do the following:

Reading up on how to move from a managed to a referenced Aperture library (pros, cons, howto),
Determine the SSD size and buy it,
Backup Before Being Bloody B$#!@%) (I'm sure someone can fill in a word that starts with a B),
Restore from backup on the newly installed SSD (put into the 2nd optical bay),
Change Aperture from managed to referenced.

At some point I will need more storage space. Will do that by adding 3 more HDD's, configured in a RAID 0. And since my current TM is being backed up to a FW800 1TB external drive I'll probably upgrade that old thing as well.

Thanks again.
Cheers,
PhilBoogie

Sounds like a solid plan - good luck!

All SSDs bundle in extra capacity — Intel, Crucial, all of them. Most are about 7%, which for a 256 GB drive will be around 18 GB, which should be plenty given that you rarely write more than 18 GB at a time — but it still doesn't seem to help as much as you'd expect without TRIM support. Yes, it's true that SandForce drives tend to bundle more extra capacity than other controllers, but that doesn't make much of a difference according to Anandtech.

Also, how is reserving a greater number of blocks going to prolong the life of the drive? If you're still writing the same amount of data, the same number of blocks are still going to get written to, then cycled through the spare blocks via wear leveling and garbage collection. If the drive's got more blocks on it total, then yeah, that'll make it last longer, but if you're just using the same number of actual blocks and just making 240 GB available to the file system instead of 256, then I don't see how that's going to make a huge difference unless you keep the SSD filled to capacity all the time.

With that said, the SandForce drives do have a longevity advantage because of the data compression they use. Sure, it won't help with already compressed data, but an awful lot of the data on your drive isn't compressed, and a SandForce drive will reduce the wear by cutting down on writes.

The argument about TRIM support in the OS is a specious one. TRIM support in the OS will be found in the file system drivers. These are one of the most heavily tested areas on the system. If the FS drivers in your OS are buggy, then you're in for a world of hurt whether the drivers have TRIM support or not, and frankly, I'd rather trust something like this to the FS drivers than to someone else (and yes, the garbage collection in SandForce and other drives does rely on querying the filesystem, at least according to Anand). There's absolutely nothing wrong with letting the drive know which blocks are free so that it can more efficiently manage itself — all TRIM is is an updating of old flawed assumptions about the implementation details of storage devices. Garbage collection is merely a workaround for the OS thinking everything is a spinning disc, and once all the major OSes support TRIM (which they must, eventually — it's an official part of the SATA specification), there will be little purpose for it anymore.

Huh? How about this for a quote:


Extra capacity (or spare area as Anand calls it) most definitely makes a difference.

Source Article

All I know is my Intel drive dies within a couple of months, and my SandForce based drive is just as quick today as the day I installed it. Theoretical discussions and synthetic benchmarks are interesting, but what is more useful to me is today the drive works just fine and today TRIM is totally unnecessary.

That article is talking about performance under conditions where you're writing a very large amount of data to the drive very quickly and often, which can occur in enterprise-level situations, such as a server. In those conditions, of course you need a large spare area, since both TRIM and idle-time garbage collection take time to clear up free space, and if you're putting constant stress on the drive such that you outrun them, you could use up the spare area, increase write amplification, and hurt performance. I'm not saying more spare area is a bad thing. I just don't think it's a panacea that can completely replace TRIM, which is a much more thorough solution to the problem (if you read the article I linked, it claims that lowering the spare area on a SandForce drive will not result in a noticeable drop in performance — under ordinary conditions, of course). I'm also not saying that SandForce drives aren't the best solution for Mac users at the moment — they certainly are, since OS X doesn't support TRIM yet. Once it does, however, I suspect that all this "TRIM is bad" talk that you tend to hear on Mac message boards and nowhere else will disappear before too long.

will the OCZ Vertex 3 require trim to maintain performance over time?

DocNoc42, thanks for the very informative post. So I gather I should go for a Sandforce based SSD for my 2009 13" MBP. right? The cheapest 64GB I could find on Amazon is Adata S599 for $120 or so. Will you recommend this SSD or do you think I must go for some other brand? Will appreciate your reply.