Installed Ram Upgrade in New iMac

Posted:
in Current Mac Hardware edited January 2014
Justed wanted to post this because i've seen a few newer members ask the question about ram upgrades in the new iMacs.



It's a bit different than what you might be use to if your a PC user or if you have done this on older iMacs with clips that hold the ram modules.



First off the new iMacs will hold either 1 or 2 gig SO-Dimm 667mhz, DDR2 200 pin, CL5 rated. You can get this pretty much anywhere. Most will rate this as PC2-5300 for the exception of OCZ which rates their 667mhz ram at PC2-5400, which will not be an issue.



I picked up a 2 gig stick of OCZ ram yesterday, 99.00, unplugged and flipped the Mac over with the screen facing down, unscrewed the plate and you will have to slide out a plastic black tab, this is used to eject ram instead of the older style clips.



Seating the ram isn't what I would call tricky but you never hear a click and don't really feel a pop or feel it seat in you have to give it a pretty good push to make sure its al the way in there. Just check to make sure it lines up with the other module , these ar side by side not top/bottom.



Putting the face plate back on was actually the biggest pain out of everything that little screw just simply did not want to catch but finally it did and booted back up no problem 3gigs of ram recognized.



Checked both banks and they checked out fine.



So for those wanted to know if you needed to match 1gig to 1gig modules you don't because the new iMacs do not support dual channel memory, I verified this with both Apple and OCZ and its also posted on the Crucial website. The simple fact that the iMac ships with just one SO-Dimm instead of two would support the fact that it uses the Ram as an entire bank of memory and is not dual channel, unlike the Macbooks which require matching modules.



So for anyone asking about this the ram upgrade went without any issues. Hope this helps anyone that is new and was nervous about upgrading themselves.

Comments

  • Reply 1 of 18
    nvidia2008nvidia2008 Posts: 9,262member
    This thread says different : http://forums.macrumors.com/showthread.php?t=339311



    By Jiminy, the guesswork posters are out in force - suggestion -- if'n you don't know the answer please don't fake it just for the sake of posting. Either do your research first, or wait and learn.



    This is an omnibus answer.



    1) All intel Macs support Dual Channel memory access if matching modules are installed. The customary estimate is that this gives a 6% - 8% real world performance benefit



    2) All intel Corexxxx Macs will run with mismatched RAM, at the loss of the Dual Channel speedup. This means



    3) All Core2Duo (and Core2Extreme) Macs can run a 3 Gb configuration (1 Gb + 2 Gb) which on average can be faster than a 2 Gb matched pair if you are using heavy programs like Photoshop that can benefit from the extra 1 Gg.



    4) All Corexxx Macs use the same DDR2-667 (PC2-5300) SODIMMs. Therefore, choosing MacBook Pro RAM for the new iMacs is correct.



    5)They do not benefit from 800 MHz SODIMMs. This is a hardware limitation of the memory controller on the motherboard.



    6) Core2Duo Santa Rosa machines, (MBP and the new iMacs) can recognize a full 4 Gb of RAM.

    Core2Duo machines can recognize a potential 3.3 Gb (with 2 x 2 Gb installed... the top 700 Mb is wasted),

    CoreDuo and CoreSolo machines max out at 2.0 Gb.

    Again, this is a hardware memory controller limitation of each chipset.



    7) 4 Gb SODIMMs (if you could find any) will not work in any Mac to date.



    8) Points 5) 6) and 7) will NOT be altered by a future OS or firmware update.



    The most-recommended USA sellers on MR are Data Memory Systems, OWC (MacSales) and Crucial (use the link at the top of the page)

    As mentioned, the Kingston KTA-MBP667xxx series are good too. Look for a reputable seller with good shipping and return policies (no shipping or restocking charges on DOA RAM, for example), and good customer service.



    Installing third party RAM is fine with Apple and does not void a warranty. Instructions for D.I.Y. installation are on the Apple Support site.

  • Reply 2 of 18
    Quote:
    Originally Posted by nvidia2008 View Post


    This thread says different : http://forums.macrumors.com/showthread.php?t=339311



    By Jiminy, the guesswork posters are out in force - suggestion -- if'n you don't know the answer please don't fake it just for the sake of posting. Either do your research first, or wait and learn.



    This is an omnibus answer.



    1) All intel Macs support Dual Channel memory access if matching modules are installed. The customary estimate is that this gives a 6% - 8% real world performance benefit



    2) All intel Corexxxx Macs will run with mismatched RAM, at the loss of the Dual Channel speedup. This means



    3) All Core2Duo (and Core2Extreme) Macs can run a 3 Gb configuration (1 Gb + 2 Gb) which on average can be faster than a 2 Gb matched pair if you are using heavy programs like Photoshop that can benefit from the extra 1 Gg.



    4) All Corexxx Macs use the same DDR2-667 (PC2-5300) SODIMMs. Therefore, choosing MacBook Pro RAM for the new iMacs is correct.



    5)They do not benefit from 800 MHz SODIMMs. This is a hardware limitation of the memory controller on the motherboard.



    6) Core2Duo Santa Rosa machines, (MBP and the new iMacs) can recognize a full 4 Gb of RAM.

    Core2Duo machines can recognize a potential 3.3 Gb (with 2 x 2 Gb installed... the top 700 Mb is wasted),

    CoreDuo and CoreSolo machines max out at 2.0 Gb.

    Again, this is a hardware memory controller limitation of each chipset.



    7) 4 Gb SODIMMs (if you could find any) will not work in any Mac to date.



    8) Points 5) 6) and 7) will NOT be altered by a future OS or firmware update.



    The most-recommended USA sellers on MR are Data Memory Systems, OWC (MacSales) and Crucial (use the link at the top of the page)

    As mentioned, the Kingston KTA-MBP667xxx series are good too. Look for a reputable seller with good shipping and return policies (no shipping or restocking charges on DOA RAM, for example), and good customer service.



    Installing third party RAM is fine with Apple and does not void a warranty. Instructions for D.I.Y. installation are on the Apple Support site.







    This persons post from Macrumors makes no sense at all. If you have a system and it supposts dual channel if you change over to single change by installing mis matched ram you lose 50% not 6-8%.



    Of course all the Intel current chipsets support Dual Channnel Memory that doesn't mean its turned on.



    Notebook chipsets almost never support dual channel because their front side bus is not fast enough to take advantage of the dual channel support, which is the case of the iMac.



    It is very clear in all of Apples documentation that the Macbook is the only product that has an issue with matching modules do to how the internal intergrated graphics uses memory.



    Also adding memory NEVER EVER makes your system faster if you don't need the extra memory.
  • Reply 3 of 18
    shanmugamshanmugam Posts: 1,200member
    Quote:
    Originally Posted by extremeskater View Post




    Also adding memory NEVER EVER makes your system faster if you don't need the extra memory.



    i like this
  • Reply 4 of 18
    Quote:
    Originally Posted by shanmugam View Post


    i like this



    Why you think it does? Does putting a bigger gas tank on your car make it go faster? Also if your that smart or think you are maybe you can explain how its truly running dual channel when the front side bus is not double the speed of the DDR2 ram? Dual channel only truly works if the bus speed can take advantage of the mhz, thats why those of use that overclock on pc's by ram at higher specs so it will support overclocking and the ram will not be a bottleneck.



    I understand because mac are like the AOL of computers that no one on this site will have a clue what im talking about. Saying something supports dual channel and it actually taking advantage of dual channel are two very different situations.



    Don't laugh when you have no clue what you are talking about.
  • Reply 5 of 18
    shanmugamshanmugam Posts: 1,200member
    Quote:
    Originally Posted by extremeskater View Post


    Why you think it does? Does putting a bigger gas tank on your car make it go faster? Also if your that smart or think you are maybe you can explain how its truly running dual channel when the front side bus is not double the speed of the DDR2 ram? Dual channel only truly works if the bus speed can take advantage of the mhz, thats why those of use that overclock on pc's by ram at higher specs so it will support overclocking and the ram will not be a bottleneck.



    I understand because mac are like the AOL of computers that no one on this site will have a clue what im talking about. Saying something supports dual channel and it actually taking advantage of dual channel are two very different situations.



    Don't laugh when you have no clue what you are talking about.



    Man you are very serious, i just kidding, i meant that same way you said, lot of us using LOTS OF MEMORY when the full usage of that memory very rare. i agree with you for everything you said, but you took my post wrongly
  • Reply 6 of 18
    Quote:
    Originally Posted by shanmugam View Post


    Man you are very serious, i just kidding, i meant that same way you said, lot of us using LOTS OF MEMORY when the full usage of that memory very rare. i agree with you for everything you said, but you took my post wrongly





    Sorry my bad. Im just use to people jumping all over others on this site for no reason. You know the ones that think you have to have used a mac since birth to be worthy to post here..lol.



    Sorry I acted like an ass.
  • Reply 7 of 18
    royboyroyboy Posts: 446member
    Quote:
    Originally Posted by extremeskater View Post


    ......



    extremeskater,



    You seem to know a lot about memory, so I have a question about the Mac Pro and 256bit addressing which, as I understand it you have to have a set of matched quads. Since the Mac Pro comes with 2x 512 mb FB-DIMMs, would adding 4 x 1G FB-DIMMs in slots 1, 2, 3, and 4 and moving the 2 x 512mb to slots 5 and 6 be the best approach?
  • Reply 8 of 18
    Quote:
    Originally Posted by Royboy View Post


    extremeskater,



    You seem to know a lot about memory, so I have a question about the Mac Pro and 256bit addressing which, as I understand it you have to have a set of matched quads. Since the Mac Pro comes with 2x 512 mb FB-DIMMs, would adding 4 x 1G FB-DIMMs in slots 1, 2, 3, and 4 and moving the 2 x 512mb to slots 5 and 6 be the best approach?





    I believe it would go like this



    4 X 1GB Slots A1,A2,B1,B2

    2 X 512MEG Slots A3,A4



    You are using 6 modules which isn't the best option also 512meg modules are single not dual ranked but I believe the above would give you the best performance.
  • Reply 9 of 18
    royboyroyboy Posts: 446member
    Quote:
    Originally Posted by extremeskater View Post


    I believe it would go like this



    4 X 1GB Slots A1,A2,B1,B2

    2 X 512MEG Slots A3,A4



    You are using 6 modules which isn't the best option also 512meg modules are single not dual ranked but I believe the above would give you the best performance.



    Thanks for the information. Hopefully, within the near future, the Mac Pros will come with 2 X 1G, but I'm not holding my breath.
  • Reply 10 of 18
    Quote:
    Originally Posted by Royboy View Post


    Thanks for the information. Hopefully, within the near future, the Mac Pros will come with 2 X 1G, but I'm not holding my breath.



    Yeah that would be nice, Apple aways seems to be a bit cheap with it comes to the ram and gpu. Its hard to believe a Mac Pro comes with 1gig and a 7300 vid standard.
  • Reply 11 of 18
    nvidia2008nvidia2008 Posts: 9,262member
    Quote:
    Originally Posted by extremeskater View Post


    This persons post from Macrumors makes no sense at all. If you have a system and it supposts dual channel if you change over to single change by installing mis matched ram you lose 50% not 6-8%.



    This is a bit weird, that's like saying if you have twice the amount of RAM in your system you will gain 200% over your original system speed.



    Quote:
    Originally Posted by extremeskater View Post


    Of course all the Intel current chipsets support Dual Channnel Memory that doesn't mean its turned on.



    Notebook chipsets almost never support dual channel because their front side bus is not fast enough to take advantage of the dual channel support, which is the case of the iMac.



    It is very clear in all of Apples documentation that the Macbook is the only product that has an issue with matching modules do to how the internal intergrated graphics uses memory.



    Officially, yes. Unofficially, while I have not worked with Macs since I was born, I do work part-time at an Apple reseller, and I can tell you the white iMacs have issues with even mixed brands of RAM sometimes. Experience dictates, and I would suggest, always used matched pairs of exactly the same brand and spec of RAM, exactly the same size, to have margin for successful, maximum performance for your buck, and peace of mind. Whether single only or dual channel is fully activated, this is my personal recommendation. Yes, I have used even PC brand RAM for Mac, and also I am typing this on a Black MacBook 2ghz Core2Duo that has two totally different brands of 1GB DDR2 667mhz. Yes, we have installed 2gb to the other slot of the new iMacs to bring it to 3gb. This works, should be stable, but like I mentioned I have seen over time, say 5 to 12months down the line, problems with system stability on the white Core2Duo iMacs with different brand/ different size RAMs. It is highly possible nonetheless that Apple has made things more flexible with the new iMacs so that mismatched RAM pairs (brand/size/etc.) will pose less of a risk... We'll have to wait and see.



    Quote:
    Originally Posted by extremeskater View Post


    Also adding memory NEVER EVER makes your system faster if you don't need the extra memory.



    Yes, but given the applications run and the way people use Macs nowadays, 2gb compared to 1gb definitely improves the system overall. 4gb compared to 2gb, yes, 4gb may be excessive for basic users.



    Quote:
    Originally Posted by extremeskater View Post


    Why you think it does? Does putting a bigger gas tank on your car make it go faster? Also if your that smart or think you are maybe you can explain how its truly running dual channel when the front side bus is not double the speed of the DDR2 ram? Dual channel only truly works if the bus speed can take advantage of the mhz, thats why those of use that overclock on pc's by ram at higher specs so it will support overclocking and the ram will not be a bottleneck... I understand because mac are like the AOL of computers that no one on this site will have a clue what im talking about. Saying something supports dual channel and it actually taking advantage of dual channel are two very different situations.



    I know you apologised for this statement, so I won't comment too much. Saying "Macs are like the AOL of computers", is a highly incendiary comment though.
  • Reply 12 of 18
    nvidia2008nvidia2008 Posts: 9,262member
    Quote:
    Originally Posted by extremeskater View Post


    Yeah that would be nice, Apple aways seems to be a bit cheap with it comes to the ram and gpu. Its hard to believe a Mac Pro comes with 1gig and a 7300 vid standard.



    Quote:
    Originally Posted by Royboy View Post


    Thanks for the information. Hopefully, within the near future, the Mac Pros will come with at least 2 X 1G, but I'm not holding my breath.



    Yeah, it is frustrating with Apple sometimes, but depending on when you get your Mac Pro, anyone using a Mac Pro now would have to go with at least 4x1gb FBDimms when buying a new Mac Pro. (4gb total)



    On the GPU side, yeah, I don't understand what is going on, honestly. I may be a very strong Apple Apologist, but I am also human.
  • Reply 13 of 18
    lundylundy Posts: 4,466member
    Quote:

    Also adding memory NEVER EVER makes your system faster if you don't need the extra memory.



    I think you have to define "need." Maybe you aren't familiar with the Mach kernel, but it will cache aggressively everything it can - applications, file-mappings for data files, and all kernel extensions. If you have 2 GB and launch PhotoShop and do some stuff, then 2 hours later launch it again, it's far more likely to still be cached if you have 4 GB rather than 2 GB, because Mach is very clever in how it caches objects. Mach will try and keep real RAM as full as possible, so the concept of "free memory" is not valid on a Mac OS system - the less free memory, the better. Mach also uses the VM system to memory-map files, so you will see a lot of page-ins by the dynamic pager that do NOT represent translation faults - they are a normal way of loading files into memory.
  • Reply 14 of 18
    lundylundy Posts: 4,466member
    Quote:

    I know you apologised for this statement, so I won't comment too much. Saying "Macs are like the AOL of computers", is a highly incendiary comment though.



    Yeah, I was all set to pop him for that until you quoted it...
  • Reply 15 of 18
    Quote:
    Originally Posted by lundy View Post


    I think you have to define "need." Maybe you aren't familiar with the Mach kernel, but it will cache aggressively everything it can - applications, file-mappings for data files, and all kernel extensions. If you have 2 GB and launch PhotoShop and do some stuff, then 2 hours later launch it again, it's far more likely to still be cached if you have 4 GB rather than 2 GB, because Mach is very clever in how it caches objects. Mach will try and keep real RAM as full as possible, so the concept of "free memory" is not valid on a Mac OS system - the less free memory, the better. Mach also uses the VM system to memory-map files, so you will see a lot of page-ins by the dynamic pager that do NOT represent translation faults - they are a normal way of loading files into memory.



    Correct this is the way an unix based OS manages memory, however that wasn't what I was disputing. Even still Photoshop CS3 is still a 32bit program and can only access 3gigs of ram without paging out. I use CS3 quite often and have yet to page out using 3 gigs of ram.



    My point was adding ram does not speed up the system unless you hit that ceiling if someone is using MS office or web browsing then they will not see any increased by with 4 gigs of ram compared to 1gig.



    Page outs are what slows down a system so if you can avoid that then adding ram will increase system speed.
  • Reply 16 of 18
    Quote:
    Originally Posted by lundy View Post


    Yeah, I was all set to pop him for that until you quoted it...



    Come on that was funny. In a way its true when it comes to the hardware, you get what they give you and you get it the way Steve Jobs wants you to have it. Hell im shocked they even let you upgrade ram in these systems.
  • Reply 17 of 18
    Quote:
    Originally Posted by nvidia2008 View Post


    Yeah, it is frustrating with Apple sometimes, but depending on when you get your Mac Pro, anyone using a Mac Pro now would have to go with at least 4x1gb FBDimms when buying a new Mac Pro. (4gb total)



    On the GPU side, yeah, I don't understand what is going on, honestly. I may be a very strong Apple Apologist, but I am also human.



    Well Apple seem to be big on loading up on what they give your on the core (cpu) then making you pay big time for ram and gpu upgrades.
  • Reply 18 of 18
    Quote:
    Originally Posted by nvidia2008 View Post


    This is a bit weird, that's like saying if you have twice the amount of RAM in your system you will gain 200% over your original system speed.







    Officially, yes. Unofficially, while I have not worked with Macs since I was born, I do work part-time at an Apple reseller, and I can tell you the white iMacs have issues with even mixed brands of RAM sometimes. Experience dictates, and I would suggest, always used matched pairs of exactly the same brand and spec of RAM, exactly the same size, to have margin for successful, maximum performance for your buck, and peace of mind. Whether single only or dual channel is fully activated, this is my personal recommendation. Yes, I have used even PC brand RAM for Mac, and also I am typing this on a Black MacBook 2ghz Core2Duo that has two totally different brands of 1GB DDR2 667mhz. Yes, we have installed 2gb to the other slot of the new iMacs to bring it to 3gb. This works, should be stable, but like I mentioned I have seen over time, say 5 to 12months down the line, problems with system stability on the white Core2Duo iMacs with different brand/ different size RAMs. It is highly possible nonetheless that Apple has made things more flexible with the new iMacs so that mismatched RAM pairs (brand/size/etc.) will pose less of a risk... We'll have to wait and see.







    Yes, but given the applications run and the way people use Macs nowadays, 2gb compared to 1gb definitely improves the system overall. 4gb compared to 2gb, yes, 4gb may be excessive for basic users.







    I know you apologised for this statement, so I won't comment too much. Saying "Macs are like the AOL of computers", is a highly incendiary comment though.



    Well im currently using a iMac and I have a Mac Pro so the AOL comment was joking.



    The issue I had with the Mac Rumors person was he was getting on someone else and he really had no clue what he was talking about.



    As an example the front side bus for the iMac is 800mhz so to say that it can take advantage of 667mhz ram in dual channel mode is just not possible because the bus speed is a bottleneck.



    This is why the Conroe chips now 6x50 have a front side bus of 1333mhz which if you do the math is just about double 667mhz (1334) this is why desktops can take advantage of true dual channel and moble chipsets can not.



    Having more ram is never bad if it keeps you from having to page out but for the average user 4gigs is most likely a waste.



    As far as matching ram modules its of course best to match the speed/cl rating but less important on after to match size 1gig compared to 2gig.



    Alot of users tend to believe that with ram it either works or it doesn't thats pretty much the case with most solid state electronics.



    As far as stability I guess time will tell if Santa Rosa chipsets will work better with mis matched ram. So far ive had zero issues, hopefully it will stay that way.
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