robpgreer Posted January 24, 2005 Share Posted January 24, 2005 I have 4 x 1GB Corsair VS1GB400C3, an Asus A8N-SLI Deluxe Motherboard and am running Windows XP Professional. My motherboard BIOS shows that I have 4GB of memory, but Windows XP only shows that I have 2.75GB of memory. Can anyone share why the other 1.25GB are not available in XP? I've called Asus and they blame XP. But I know that XP can recognize up to 4GB. And Corsair shows that this memory is supported on this motherboard. Please help! Thanks, Rob Link to comment Share on other sites More sharing options...
Corsair Employee RAM GUY Posted January 24, 2005 Corsair Employee Share Posted January 24, 2005 Well yes, it can see 4.0 Giga-Bit, but that would be minus the memory and cache in your Video card and CPU. In addition, Windows will only allow 2.0 available to programs. The rest of the memory is used by the O.S. kernel and or for PCI devices. Link to comment Share on other sites More sharing options...
robpgreer Posted January 24, 2005 Author Share Posted January 24, 2005 Well yes, it can see 4.0 Giga-Bit, but that would be minus the memory and cache in your Video card and CPU. In addition, Windows will only allow 2.0 available to programs. The rest of the memory is used by the O.S. kernel and or for PCI devices. Thanks for the quick response! But I'm not sure I was clear in my initial post however. With 4GB of physical memory, Windows XP is only reporting that 2.75GB is physically available in the machine. The motherboard bios is reporting that there is 4GB available. After speaking to one of the Asus 2nd level techs, he suggested that the NForce4 chip set is not allowing the allocation of that other 1.75GB of physical memory. And that's why XP is only showing what it sees ... 2.75GB. Does that make sense? I'm familiar with the 2GB application memory barrier but I don't think this is related. And since I'm using a Radeon X800 Pro with a AMD64 4000+ I don't think the memory is being siphoned off to video cache. I'm sorry if this post sounds a little dense as I'm sure I'm not as technical as some folks on this forum. So do you think the problem is with the chipset or could it be something else? I'm just convinced that if it is not a chipset problem, then the 4GB would show up as being installed, regardless of whether or not XP could use it all. Thanks! Rob Link to comment Share on other sites More sharing options...
Corsair Employee RAM GUY Posted January 24, 2005 Corsair Employee Share Posted January 24, 2005 Rob, Its not a problem, it is as ASUS has told you a limitation of the O.S. Try and run http://www.memtest.org on the system and see how much Ram is available. Link to comment Share on other sites More sharing options...
robpgreer Posted January 30, 2005 Author Share Posted January 30, 2005 Rob, Its not a problem, it is as ASUS has told you a limitation of the O.S. Try and run http://www.memtest.org on the system and see how much Ram is available. According to the BIOS it says 4GB. According to Memtest v3.2, I have 2.816GB. So what does it all mean? Is there no way to actually access and utilize 4gb in a normal desktop machine? I just don't understand where the bottleneck is in my machine. Did I purchase the wrong motherboard? Did I purchase the wrong RAM? Thanks for your speedy replies so far! Rob Link to comment Share on other sites More sharing options...
Wired Posted January 30, 2005 Share Posted January 30, 2005 It's not the mobo or memory, since the BIOS sees all 4 GBs. It is Windows. If you go to a server OS, it'll see it all most likely. Link to comment Share on other sites More sharing options...
deckard Posted July 4, 2005 Share Posted July 4, 2005 I have this exact memory and MB. WinXP Pro x86 reports about 3GB for me, I suspect I have less HW installed then you do. The BIOS, memtest86+, and WinXP Pro x64 all report 4GB. What you are seeing is, as noted above, a limitation of 32bit WinXP. I dual boot XP x86 and XP x64. Other then a missing driver for my printer, XP x64 is working well. Buyer beware, but you might consider upgrading. MS is allowing upgrades for free: http://www.microsoft.com/windowsxp/64bit/upgrade/default.mspx As a side note, does memtest86+ show any problems with your system? I am asking because memtes86+ shows problems in my system. I may start a new thread for that though. Link to comment Share on other sites More sharing options...
Garvin Posted July 4, 2005 Share Posted July 4, 2005 A Microsoft article on the subject: http://support.microsoft.com/default.aspx?scid=kb;en-us;888855 Link to comment Share on other sites More sharing options...
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