4GB revisited

[lambros]

I guess that this is a dead-end situation, but I would welcome any suggestions.

PC1: Gigabyte motherboard, Athlon X2 4600+, 4GB Geil DDR 400 dual channel (4x1GB sticks), XP pro SP2 (32bit)

Initially, only 2GB were installed, so I went and bought another 2. Upgraded the mobo BIOS to latest version (I had to install the new processor as well) and when I inserted the extra memory, mobo would not recognize the extra memory. Entered BIOS, hit CTRL+F1 to reveal Advanced settings, checked the "memory remapping" feature as suggested in relevant internet fora, and voila: 4096 MB on POST. I enabled the /3GB switch in boot.ini and windows (32bit) recognized 3.25 GB, which is fine for me at the time being.

Actually, I read that XP subtract PCI and PCIe devices from total memory, and while they do not really use that memory, they use that particular address range.

PC2: new system, ASUS P5B Wifi Deluxe mobo, Core Duo 2 6400, 4GB Kingston DDR2 667 (4x1GB sticks), XP pro (still 32 bit).

I built the system myself, and it would not post with all 4GB installed. I enabled the memory remapping feature, but still would not post at all. I removed one stick, and it did post. I switched all sticks to ensure that none was faulty, and there was no problem. It would not accept all 4 sticks. I flashed the bios with the latest version, but to no avail. I looked up the manual, and I found out that the particular Kingston memory was not supported in all 4 modules (I wonder why!!!). Only in channel A or B, so that was just 2 GB for me. I installed windows with 2GB ram with no problems.

I spent two days reading hardware threads in the internet, and tried almost everything.

Then it dawned to me to take another look at the ASUS certified memory sticks, and saw that the 533 Kingston sticks were accepted in all slots. So, I enabled manual DRAM timing, and changed it from AUTO (which is 667) to 533. I inserted all 4 sticks, and magically the BIOS posted with 4096MB. But when XP loaded up, only 2GB would be shown in the Task Manager and the System Properties. I ran the CPU-Z utility and it showed 4GB.

Now, that is weird... CPU-Z shows 4GB and XP recognizes only 2. I expected 3.25 GB, since my other PC has a 256MB PCIe VGA too, and no other PCI card inserted as well. No matter how many boot.ini switches I tried (/PAE, /USERVA=xxx, /3GB, /LARGEMEMORYAWARE) XP would only show 2GB in that case.

I know that in several months time Vista will come out, all memory problems will be solved, but it just drives me nuts not being able to find out what the problem is.

Any suggestions?

[Jason Matthews]

Sorry I can't offer any suggestions but this is very odd. I too am interested in the fix for this.

[CookiE]

Sorry I can't offer any suggestions but this is very odd. I too am interested in the fix for this.

I know windows xp can only reconise 4gig total ram so not sure if that includes ram on the graphics card or not.

So its a windows problem there is a reg thing you can change that is to do with max memory looking for it but havnt used it in ages.

Also have you got all the latest xp updates etc that might be something worth doing

[lambros]

thx guys. All updates are installed, I also checked HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management and everything seemed OK.

[Elliot]

Lambros

 

I have the same problems on both of my Opteron machines. On the first Opteron I use a Tyan motherboard, the other machine has a SuperMicro motherboard. Not only they do not recgonize all of the memory, but when I populate the motherboards with more the 2gb of memory, the Viz 2005 crashes more often when doing a complex image.

 

I used Corsair memory sticks..... I gave up and just run the units with 2gb.... I am building a new unit and will install the Windows 64 bit version to see if I can do better on memory management. Please let us know if make any progress. I have tired everything they have told me and no luck.

 

Thanks

Elliot

[puciorek]

I have just finished building computer with 2 opterons (280), Tyan motherboard, 4 GB ECC memory. Originally, windows xp 64 would not recognize 4GB, however if you tweak your bios, it eventually will.

F.Y.I., I had problem with ASUS K8N-DL where it would restart without any reasonable explonation. I returned this MB and replaced it with TYAN S2877 and it works fine (very stable). TYAN came with the latest BIOS version, so there was no need to flush it and upgrade it like I did with ASUS.

In conclusion, please be aware that even after switching to windows 64 you still may want to modify your BIOS settings.

Best of luck.

Darius