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RAM count problems on Dimension XPS Gen 4
'Twas a simple process. I have some out-of-warranty Dimension XPS Gen 4 workstations in my lab that we're phasing out. However, no one wanted to toss the hardware altogether, so we took the peripherals and RAM from half of them and tossed them into the other half. Ideally, this should have resulted in half the number of Dells (3) with twice the amount of RAM (4.0 GB). As I said: simple.
While the BIOSes of the remaining machines do indeed report four 1.0 GB DIMMs installed on each board, no OS nor utility can see all 4 gigs. They all report only 3.0 GB available. I've tried 64b Linux distros (Ubuntu 10.04 LTS and 12.04 LTS plus Debian 6.0.6), 64b Win7 Enterprise, as well as 32b and 64b memory diagnostic software. None of them see all 4 GBs of RAM which I've installed.
Utilizing Memtest+ v4.20, I've tested each DIMM by itself and with every pairwise combination in each DIMM slot. I even tested three of them together at once. In every case, multiple passes came out clean. The DIMMs and the motherboard seats are good. I even upgraded the BIOS of my testbed machine to A07, the most recent version released by Dell (in Summer of '05). No difference. This is happening with the other two jalopy Dells as well, so clearly this isn't a software issue; it's a hardware configuration issue. How do I proceed?
Thank you for your time and consideration.
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Posted February 7th, 2013 13:00
The RAM is indeed not available to Windows, but I seriously doubt something is reserving it for non-user functions.
I'm running a 64-bit edition of Windows 7 Enterprise. On many other machines I've built, 64-bit OSes have no problem seeing and utilizing all 4 GB, 8 GB, and even 16 GB of RAM on the board. To reiterate, in the case of this Dimension XPS Gen 4 desktop computer, no 64-bit operating system I've installed seems capable of accessing that last 1 GB. Thus, this isn't likely a software problem.Additionally, if I take out one of the DIMMs, the system no longer exhibits this 1 GB of RAM "being set aside." If something in the hardware needed that 1 GB of RAM for non-user functions, it would still need it if there's only 3 GB. This would leave only 2 GB of RAM for the operating system. This is not the case, however. With only three 1 GB DIMMs on the board, none of the RAM is reserved. This is true on all of the 64-bit OSes I tried. Of course, only having three DIMMs on the board fouls up the two dual-channel DDR scheme as one DIMM is on a channel by itself.
As a side note, if the hardware is reserving 1 GB system RAM for other applications, it's not for a video buffer. These Gen 4 desktops have PCIe NVidia GPUs; GeForce 6800 series cards, to be precise. The GPUs have dedicated RAM built in.328
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Posted December 29th, 2014 15:00
I have an XPS Gen4 as well, A07 BIOS.... I read in multiple places that the motherboard that shipped with the machine is not compatible with 64bit OS. Perhaps if you downgrade to 32bit Windows 7 it might see all 4 gigs?
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Posted December 29th, 2014 16:00
I have an XPS Gen4 as well, A07 BIOS.... I read in multiple places that the motherboard that shipped with the machine is not compatible with 64bit OS. Perhaps if you downgrade to 32bit Windows 7 it might see all 4 gigs?
Why are you responding to a post that's almost 2 years old?
A 32-bit OS will see all 4GB of RAM but will only use ~3.2-3.5 GB of it...
RoHe
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328
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Posted February 6th, 2013 16:00
If BIOS is seeing 4 GB but Windows is only seeing 3 GB, that probably means some RAM is being set aside for other use and not available to Windows. Eg, Some RAM may be set aside for video, which is fairly common occurrance on older systems using onboard video or if an add-in video card doesn't have any / enough RAM of its own.