Windows XP 64-bit shows less RAM than the amount installed Tags: Ubuntu RAM Windows XP Last response: November 4, 2010 6:11 PM in Windows XP Share alecz20 November 2, 2010 9:01:19 PM Hello This is the system in question: - 64-bit CPU (Intel i5 750) - 64-bit Motherboard (Asus P7P55M) - 64-bit Windows XP - 64-bit Ubuntu 9.10 - 4 GB RAM installed - separate Video Card (ATI Radeon HD 5770 - 1 GB Video RAM) The BIOS, Memtest86+, and Ubuntu, all show 4.0 GB of RAM in the system Windows XP x64, however, shows 3.5 GB of RAM installed. Question: Why is it that only Windows x64 show less RAM, while everyone else shows correct amount? I also HAD Ubuntu 32-bit, and it showed 2.9 GB, so Ubuntu would show the 32-bit limitation. Then I installed Ubuntu 64-bit, and I can see 3.9 GB (for some reason it doesn't show 4.0, but that's minor) Windows XP x64 (YES I am sure it is the 64-bit version) shows 3.5 GB of RAM Memory remapping in BIOS is turned ON, but I don't remember if I turned it on before or after I installed Windows. It was definitely ON before I installed Ubuntu 64-bit. Now if I toggle memory remap ON/OFF, I see that everyone detects only 3.5 GB with memory remap OFF, but with memory remap ON only XP detects 3.5 GB. Note: There is no on-board video on this motherboard, so the argument that memory is reserved for the video-card is invalid. Any ideas? More about : windows bit shows ram amount installed rexter November 4, 2010 4:33:24 AM What service pack do you have? Don't know if you've check this one already. http://en.wikipedia.org/wiki/Physical_Address_Extension... m 0 l alecz20 November 4, 2010 5:57:27 PM I have Service Pack 1. I don't know what you wanted me to see on that link. The only relevant information is that it says that Windows XP 64-bit (which I have) supports up to 128 GB of RAM. Maybe I'll try to upgrade to a newer service pack (if it exists) m 0 l Can't find your answer ? Ask ! Get the answer rexter November 4, 2010 6:11:54 PM I gave you the wrong link, anyway there was a discussion on one forum that one person manage to see the RAM corectly by updating to XP SP2. just wondering if you did so already? http://www.microsoft.com/downloads/en/details.aspx?Fami... m 0 l Can't find your answer ? Ask ! Publish Related resources Actually window will show less RAM than what is installed on board. The windows pc actually shows the usable quantity Forum Windows/BIOS showing less RAM than is installed.. Forum Windows 7 64bit not showing right amount of RAM Forum less ram showing than installed Forum I recently installed a 4x4GB kit of DDR3 ram onto my motherboard. Windows 7 Pro 64bit is showing I have 32GB ram (16GB usable Forum Less RAM showing than what is actually installed. Forum RAM showing less than installed Forum Help Ram Showing less than installed Forum 12gb Memory Installed Windows 7 64-bit shows 4gb Forum SolvedIf I reinstall windows xp past the end of support (less than 2 weeks away) will i still get all the existing updates? Forum SolvedWindows 8 64 bit not showing the right amount of RAM Forum SolvedWindows7 64bit 6GB RAM installed, computer only detects 4GB Forum Solved14GB RAM installed but only 7.98GB usable Windows 7 64-bit Forum SolvedMouse lagging/delayed; Windows 64bit, recently installed 2 x 2GB sticks of ram. Forum Solved8GB RAM installed Windows 8 64bit says (3.9 GB usable). Help! Forum Hard drive shows less space than i actually have in windows 7 Forum SolvedASUS P6T - Windows 7 Enterprise 64bit - Only Shows 4 of 6 Gigs RAM Forum SolvedWindows showing 16GB installed RAM but only showing 12GB total physical memory . Forum I installed more ram but it shows less Forum Solvedwindows showing less ram Forum More resources Read discussions in other Windows XP categories Configuration Customization Drivers Security Video !