maximum memory supported by Windows 7

    General discussion

  •  Windows XP Professional x64 edition supported up to 128GB and when it was released, some motherboards could be populated to that amount, so all was fine. Vista x64 was released and kept the same limit, even though motherboards have evolved, so even though scRGB support was offered in Vista, I just waited to see what would happen with Windows 7. A dual-processor Nehalem EP motherboard can support 288GB, and some software like Panorama Factory can handle over 128GB with no issue, as not constrained by the "famous llp64 ecosystem". WS2003 (same codebase as XP x64) had up to 2TB support but I want a workstation OS with all the associated support and task optimization (drivers, application software compatibility, etc...) Please advise. Thanks !
    Sunday, February 15, 2009 7:06 PM

All replies

  • Windows 7 is equated to Vista while still in the beta - so the official answer will be the 128 gB that you experience with Vista.
    The specs may change once the beta is released - but until then that's the answer to your question.
    - John
    Sunday, February 15, 2009 9:02 PM
  • Hi

    Why you want so many RAM?
    Monday, February 16, 2009 6:36 PM
  • You'll need that much to open IE 8    :-)

    Monday, February 16, 2009 6:47 PM
  • usasma, 
    official is the word, at least until another MVP tries Windows 7 beta on a machine populated with more than 128GB....
    Tuesday, February 17, 2009 3:17 AM
  • Ventsislav,
    Because I am not color blind and also I like higher resolution pictures in raw mode (think different ?).
    Not to mention that neither SCSI RAID nor SATA-bound SSD ever matched RAM disk performance...

    Tuesday, February 17, 2009 3:20 AM
  • For a 64-bit OS I can see no reason other than malfeasance to limit RAM to anything less than 18 EB. I am so fed up with artificial limitations I am jonesing to sue everyone in sight to stop the nonsense.

    My Linux server (32-bit) can see 64 GB of memory and the 64-bit vesion can see 18 EB, not that I can afford it. They just do not limit the system in any way.

    I can buy boards today that can have 256 GB of memory but I am compelled to buy Windows server. For what? The board has a PCIe slot for a video card, and another for something else so I see it as a desktop. Only 4 CPUs with 8 sticks of RAM each. It fits my current chassis no problem. Stuffed with quad-core processors, and poof, Windows cannot use it. Microsoft refused to accept the board as a desktop.

    I also loath disk limitations to the point of rancor. The latest nonsense, MBR 2 TB limit. EFI has been available for several years, so what is the hold up??

    Windows 7, beta 1, build 7 cannot install on a RAID of4 large disks, let alone 16 of them. No problem, my Linux can gobble up that job.

    I cannot get my video and monitor to go past 1600x1200 even though it can display 2304x1768 no problem. Come on, already.

    Yo Balmer, hope you're reading this.

    I am a professional developer and I am registered with Microsoft Connect. I am also a vegan. I also do web development. Economics and chess are two of my many interests.
    Tuesday, February 17, 2009 3:44 AM
  • Vegan, I am with you... 
    We had WQUXGA monitors in 2001 (3800 x 2400) and Super HiVision video in 2005 (7680 x 4320) , not to mention next year's 28K from RED and then deep color, scRGB, HDR and the native RAW codecs of Windows 7, all making memory capacity a huge priority, especially for RAM disks given the issues of context switch on threads with conventional disks....
    At least the heap was seriously boosted when XP x64 came out, but an OS that supports less than half a fully populated dual-processor motherboard might soon draw more attention then octuplets !!!
    Tuesday, February 17, 2009 4:58 AM
  • I only have an antique Dell P991, trinitron, CRT. Funding is hard to come by at that level of excellence.

    I have a CD for XP x64, was disappointed that it could not see past 2 TB. Or See > 128 GB of RAM.

    Go look at the new Tyan boards, 4 AMD CPUs and 32 memory slots. I have to use Linux desktop as Windows is crippled so badly as to be useless.

    I am a developer, matters little to be, if Microsoft wants to commit suicide, who am I to stop them.

    I friend of mine puked when I told him Windows was running on a Cray. I prefer to use CLI to run it. My web server is CLI only and it runs everything fine.

    That Red product looks nice, but out of my price range. Guess the trinitron will have to suffice another year. Still works perfect, never a problem and the color is fine. The display adapter is another grievance. Measly 8 pits per pixel, how about 64. I have searched for better adapters, no luck.

    Testing Windows 7 shows to be as crippled as Vista and XP x64.

    I took economics as well as computer science, RAM has a 45% price deflator. Talk about short time obsolescence. This is why I am screaming at the top of my lungs.

    A 64-bit CPU can see 18,446,744,073,709,551,616 bytes, so 128 GB is a real rip off.

    Want to divest of the HiVision cheap?

    I am a professional developer and I am registered with Microsoft Connect. I am also a vegan. I also do web development. Economics and chess are two of my many interests.
    Tuesday, February 17, 2009 5:13 AM
  • It is all good, but why you think W7 is the problem?

    memorized there is hardware RAM disks, so if you want buy RAM HDD and do not use RAM to make virtual drives

    Quality of pictures you see on your display depends of capabilities of your video card, but not of system RAM

    Vegan Fanatic
     who told you that your linux server can see and use 18 EB? Why 18 EB? Why not 1000 YB?

    It is all the same because cannot test it right? And even you can who tells you it will work?

    Linux server may not be limited but what will you say for linux for desktop?

    CPU can address 18EB address space, ok, but where is memory controller that can support it?

    It is good to talk but when words match facts!

    This is technical forum, but not fantasy forum right? :)

    Tuesday, February 17, 2009 6:47 AM
  •  memorized,
    did you notice not every WS2003 Server supports 2 TB? Look at the WS2003 Standard for example, please.
    The different memory limitations at different SKUs is normal practice for market segmentation.
    Unfortunately workstation with more than 128 GB RAM is very-very untypical user scenario so I'm sure the will no >128 GB support not at Win7 but at Win8 too. I'm sorry.

    your problem is different, it is hardware problem and you may check Memory Remap option or similar in BIOS to enable it.
    It is better to create a new topic if this will not help.
    Tuesday, February 17, 2009 12:10 PM
  • Ventsislav,
    Even if your SSD (what you call RAM HDD) under a RAID configuration can give me 12GB/s, you still have latency, translation layers issues, and until MRAM, the limited writes. Also just figure how much 288GB would cost me, with the Cenatek or Acard drives in RAID array in comparison to DDR3.
    As far as the quality of pictures I was referring to the source ; you definitely can see the Presidential inauguration picture on with a 800 x 600 display and 65536 colors and a 1MB video card, but handling the original image or its workflow takes a bit more than the display ; also printing does not depend on my video card. Imagine a 9 x 6 stitch of mid-resolution pictures like (4-year old asymagon lens, etc...), with 16-bit color depth and tell me how you would go about this workflow with 128GB.  
    Thanks !

    Tuesday, February 17, 2009 7:16 PM
  • Igor,

    The market segmentation is the whole issue ; what's untypical to you might not be untypical to others. Like when someone said a while back that no one would ever need more than 640K ; unfortunately not everything was written in handcrafted machine language code, double-checking assembler output and doing proper memory housekeeping after application or process terminates, etc..., and the memory pollution and fragmentation aspects became more prevalent over the years. Don't reboot for 6 months and look at your memory usage ; also workstation users might not be interested in server OS, and need different task prioritization, kernel and user ecosystem that's taylored for their needs. Also I noticed that even you have the same codebase, such as XP x64 and WS 2003 x64, there are different drivers and substitution does not always work. Vista might have been successful, but I am not sure that capping workstation OS to 128GB will be. 
    Tuesday, February 17, 2009 7:28 PM
  •  memorized,
    you add one word (ever) and this changes the old words' meaning very much.
    Well I often do not reboot for month or two or more until update requires rebooting and have no problem with memory usage. Memory pollution... hmm, I do not like bad-written programs. ;)
    The memory fragmentation really is nit an issue in most cases.
    128 GB limit for workstation Windows OS will be increased of course but not in next few years.
    Tuesday, February 17, 2009 8:32 PM
  •  The terminology varies, but the concept is comparing a magnetic hard drive with possibly 32MB of cache and RAM accessed via IMC or via SATA (like acard or gigabyte i-ram). Even assuming the SATA physical layer translation and protocol overhead is as good as SATA, you'll probably get at best 1.2GB/s with 4 acard 9010 in a raid configuration. This is far from what the integrated memory controller in the latest crop of Intel or AMD processors can achieve.
    The 4 9010 will be about $1000, whereas I can use the motherboard sockets for faster access.
    As far as picture size, no one will dictate how many pictures I want to stitch together, even though I bet it's gonna be less than
    I mention the printing for the sake of resolution and rendering, even though I direct the spooler to a RAM disk like superspeed...
    What's your opinion of DMA abstraction performance in contrast with raw IOMMU over 4GB ?

    Wednesday, February 18, 2009 5:06 AM
  • Thing are not so simple of course

    If you use RAM HDD all 128GB RAM are free for processing data if there is software can use them

    With 128GB free RAM you can stich together as many pictures as you want :)

    You can use 8 or even 16 port RAID controller to build RAID0 array

    If you want you can. There is not limit for imagination
    Wednesday, February 18, 2009 8:38 AM
  •  Ventsislav Alexandriyski I have to tell you that I have a 16 port Promise SATA/SAS PCIe x8 card and I cannot boot from it with Windows. Cannot boot > 2 TB. The controller can build as big of RAID as you have disks for, the MBR limit still applies. As a secondary storage device I can use GPT and format a larger array. I just cannot boot it yet.

    I could use a bunch of SSD as they are small in capacity but the MBR problem is still there.

    So I have to rant over disk limits, RAM limits, and the short word. Strike 3. Eventually the 64-bit CPU will be outstripped.

    I am a professional developer and I am registered with Microsoft Connect. I am also a vegan. I also do web development. Economics and chess are two of my many interests.
    Wednesday, February 18, 2009 2:27 PM
  • @Vegan Fanatic

    I have to chime in on this one.

    In reality, 32bit Windows can actually see on upwards to 64GB of RAM. Don’t believe me; load up Windows Server 2003/2008 Enterprise (32bit). The reason for the artificial limitation on the desktop is due to the driver landscape. Mark Russinovich can explain it much better than I. See:

    EFI is there. You can easily create a drive to utilize GPT (GUID Partition Table). Nothing is stopping you.

    What is RAID used for? The real reason for using RAID and the not the prevailing belief of how RAID should be implemented. How many people know the real ramifications, its benefits and detriments, to using RAID 0?

    Your OS SHOULD NOT BE INSTALLED ON A RAID 0 ARRAY!!! Never. The OS should, for redundancy purposes, be installed on a RAID 1 (mirrored) array. The data that the server or workstation uses should be installed on a RAID 5 array—following the installation of the OS (unless hardware based). When do you use RAID 0? When I/O performance trumps all other considerations to include system reliability and recovery. An example would be to capture real-time, uncompressed HD video (1280x720 at 60fps or 1920x1080 at 30 fps) for editing and post production. Even then, the user needs to make provisions for backing up the data to a server or some other location in the event of a catastrophe.

    As for your monitor issue, you need to investigate that. At work I have a Dell Precision 690 with 16GB of RAM, an NVIDIA Quadro FX4600 card that is pushing two 30” Dell monitors at their native resolution of 2560x1600 each (a total desktop resolution of 5120x1600). I have no problems or issues at all running Windows 7 x64. On one display I can have Adobe Photoshop CS3 up and running along with Autodesk 3DS Max 2009 SP1, while the other display is running Adobe Premiere CS3 capturing real-time video from a HDMI input capture card.

    If all of that is too limiting, well you always have

    Wednesday, February 18, 2009 8:47 PM
  • Well why should I have to pay for a server when all I want is a desktop. Its called a rip off as far as I see it.

    My machine has 16 GB of RAM and if I could buy it, I would use 32 GB. I use unbuffered DDR2 memory, which is faster than buffered memory by a significant margin according to RAMTEST.

    For a 64-bit OS to support < the full 18 EB address space is an artificial limitation that as far as I am concerned is intentionally obsolete in a shor time frame.

    RAM has a price deflator of about 45% historically. So in 5 years 128 GB of RAM will cost far less then it does today.

    DDR2 is limited to 8 GB per stick by the JEDEC assholes. DDR3 allows only 16 GB per stick. Why not 1024 GB and stop this nonsense in the memory business of miniscule increments. Each new generation of RAM is just a rehash of the last one, with more wait-states. The problem is the deflator beats up on RAM vendors real bad.

    All PC RAM is SDRAM which was developed in the 1970s for mainframes. PCs only began using it after the patent expired.

    As for my display, I tried custom timings, it failed. Windows seems to want to force the issue.

    As for RAID, I like RAID 6, less likely to croak. RAID 6 tolerates double disk failure while RAID 5 tolerates a single disk failure. MY Promise card supports RAID 6 among other modes. I never said I use RAID 0, that was Ventislav's idea.
    I am a professional developer and I am registered with Microsoft Connect. I am also a vegan. I also do web development. Economics and chess are two of my many interests.
    Thursday, February 19, 2009 5:27 AM
  • well my understanding is that win 7 and windows server '08 share the same codebase, and the max ram supported by server '08 is 2TB.  That said, while recent AMD chips can address 256TB, Intel chips are physically limited to only addressing 1TB, and early EMT64 chips only 64GB.

    that said, '03 server standard was limited to 16GB, '03 server R1 32GB, enterprise edition 64GB, R2 1TB.

    in '99 you could get DEC alpha workstations with 64GB of rdram.
    Thursday, February 19, 2009 9:20 AM
  • As I understand it the AM2 class CPUs from AMD suport 44 bits of addressing physically but the registers suppport 64-bits. The newer AM3 have more pins but I do not know if any more addressing bits are included.

    With address remapping, this is not a big problem, the AM2 can only use 4 sticks of a max of 8 GB for 32 GB. The AM3 can use 4 sticks fo 16 GB for a max of 64 GB if you can afford it.

    I just think Windows should not be limited severely and be able to use next gen CPUs easily. Microsoft seems to want to sell me dozens of copies of Windows over my life. I would rather buy some more games etc.

    The Tyan board uses 4 quad core processors, and I am not sure how many address pins the AMD Opterons currently have. I do know the Tyan board has 32 memory stick sockets. This means its not as fast as it could be with unbuffered RAM. I like memory bandwidth more then CPU clock.

    I am a professional developer and I am registered with Microsoft Connect. I am also a vegan. I also do web development. Economics and chess are two of my many interests.
    Thursday, February 19, 2009 3:21 PM
  • cp5184,
    All of the AMD CPU's have an 1TB physical address range (40-bit) and a 256TB (48-bit) virtual address range. If you have other technical information please post it here.
    But there is more, none of AMD's can 'drive' more than 4 memory slots, that means max. 16GB (4x4GB DDR2) for AM2+ socket CPU's and 64GB (4 x 16GB DDR3) for AM3 and F socket processors.
    None of the Alpha chips can (could) address more than 8GB, DEC's Alpha Station ES40 model can hold 4 sockets with each socket driving 8GB maximum (8x1Gb), so the maximum for the largest Alpha station (memory wise) was 32GB. This box wasn't yet available in 1999, though and we had to wait until 2003 before the extremely expensive 1GB sticks became available.
    Thursday, February 19, 2009 4:27 PM
  • Willy,

     Why is section 2.6.7 (page 68) stating 48-bits (Barcelona & Shangai) physical address range [256TB] ?

    Also AFAIK the Nehalem EP & EX will offer 44-bits [16TB] physical range.

    Understood that the IMC "load" capacity might require efficient and dense memory to take advantage of the design, but as Vegan infers, it's possible that the current recession induces manufacturers to outdo themselves and precipitate MRAM or more recent designs and spend more time in the labs than in court to all's benefit, so I would not preclude that the Win 7-era processors could be fully populated before EOL.

    Concerning the PAE and the 128GB paging of a 32-bit OS, I am not sure we'll miss it, yet I know x64 is largely an x86 extension rather than a native 64-bit design.  The same applies to heap and other handle constraints in 32-bit OS. 

    Then concerning the Workstation vs Server OS, not sure what the difference is between a WS2008 x64 and Vista or W7 x64 driver for the same device, but maybe it had to do with paged pool and the 128GB boundary...


    Friday, February 20, 2009 12:29 AM
  • The 128 GB memory limit is a joke as far as I am concerned. The price of 8 GB sticks seems to fall every week as more and more unsold sticks pile up. Soon I expect 8 GB DDR2 unbuffered to come to market as the server market dries up. Recently 4 GB sticks have come to the desktop market and I expect 8 GB to not be far away.

    One issue I have is licensing, when did a computer become a licensee? A person can enter into a co9ntract, a computer cannot. So locking an OS to a machine is moral turpitude. I buy new machines regularly.

    The PAE goes back to the late 1990s when servers exceeded the 4GB address space of a 32-bit CPU. I pointed out that the 32-bit CPU of 1986 would not last 20 years before it was outstripped. I expect the 64-bit one to be outstripped in about the same time frame.

    The AMD reworking of the CPU was meant largely to provide hardware binary compatability for 32-bit software. Microsoft provided a beta of XP soon after the first such CPU came to market some years ago.

    I would be happier with a 256-bit processor, this has enough bits to handle a lot of inflation before it chokes.

    I am a professional developer and I am registered with Microsoft Connect. I am also a vegan. Economics and chess are two of my many interests.
    Friday, February 20, 2009 2:08 AM
  • This (section 2.6.7) is somewhat misleading, in some documents they mean Physical DRAM address ranges while in other they refer to the System's Physical address ranges. The 48-bit "coherent" physical address range is used to map DRAM and MMIO. Only 40 bits (max.) are used for local DRAM access (used by the processors DRAM Controller (DCT)), the remaining 8 bits are used by the Memory Controller (MCT) to route memory requests. One possible route is another processor's DCT in a MP system. That means that a single processor can theoretically address up to 1 TB (40-bit) of local DRAM memory, and up to 4TB of system memory in a coherent fabric system (4 Processors). Note that the virtual address space of an x64 based OS, is 8TB, quite larger than 1TB, but you know where you are ending when allocating more than physically available in the system.

    About Nehalem EX/EP, it looks like the address range is 44/48 (physical/virtual), but again it's not clear (to me at least) how these will map to the local (integrated) DRAM controller, but my guess is 40 bits or max. 1 TB for DRAM, which is a fair number for a single processor (8 cores) system. Sure, the current recession will have a serious impact on the future developments in this area, who say's we will see any Nehalem EX chip and systems hitting the streets this year. 

    The drivers for the same device on W7 and Server 2008-R2 are (or can be) exactly the same, provide we are talking about x64.
    Friday, February 20, 2009 11:17 AM
  • Igor, I worry for you.... Untypical today can be standard in no time. Developers and manufacturers are watching users and economics. The initial cost of the latest technology stops most people from using it but production costs drop and user expectations rise very quickly. I doubt that there is an upper limit to how much memory and processing power we would use if it were available. Surely, rather than assuming we have a normal bell curve where only a few require high-end machines, we are facing the exponential graph where eventually everybody will NEED more processing power than anyone can imagine. Much like the phone and motor car; once a luxury now a neccessity, in future a question of survival. Surely any smart programmer or manufacturer is leaving a bit of room for growth.

    That is the cute little plankton of today is the blue whale of the future, don't try to grow it in a fish tank.
    Friday, March 13, 2009 3:53 AM
  • As far as I am concerned, the JEDEC needs to define 64-bit address bus, the CPU needs 64-bit addresses. Same for the disk access. This will keep problems at bay for a few years. Still exponential growth will take its toll.

    Each new generation of RAM merely adds wait states, it's the industries dirty little secret. JEDEC simple remaps the pins.

    Same nonsense with Windows.

    I perfer to make them an offer they can't refuse. Make it better.

    I am a professional developer and I am registered with Microsoft Connect. I am also a vegan. Economics and chess are two of my many interests.
    Friday, March 13, 2009 4:04 AM
  • Would it work with 640bit address bus Remember how quickly home computers went 16, 32, 64, 640 or should we be thinking outside the box?
    Monday, March 16, 2009 1:44 PM
  • I quote B Gates, "640KB shoud be enough for anyone". Ya right. that nonsense did not stand long at all.

    IT/Developer, Windows/Linux/Whatever I need a new web server, the antique IBM 300GL has a 137GB disk limit, for my chess site. I wanted to post many more downloadable files, the existing 30GB disk is insufficient.
    Monday, March 16, 2009 2:55 PM