XP-64 Not showing all RAM

[S0Y73NTGR33N]

I just installed XP-64 onto a brand new build. It has 4GB of dual channel memory on the motherboard, and it all shows up in the BIOS. But only 2.75 shows up in windows. Any ideas?

Here are the specs of the build

ASUS A8n-SLI Deluxe
AMD 64 3500+ 939
2 SLI - MSI NX6600GTs
4 X 1GB sticks of PQI Turbo 3200 Dual Channel 3-4-4-8

I assume the rest of the specs don't matter but ask and I'll give em.

Thanks,
Green

 

[hootpie]

I was going to tell you to check the seating of the memory and/or that your RAM might be fried, but then it would show 2 or 3 gigs, not 2.75.

Edit: Try installing Linux or XP 32bit and see if it recognizes all of your memory.

 

[Treyshadow]

Man that is a lot of ram. I am not sure what the issue is, I tried 4x1 Gig of corsair xms in a neo4 sli platinum with no issues, but only for a bit.

Good luck as that is a tough issue.

 

[imported_BikeDude]

See if you can find any PCI memory hole settings in the setup of your motherboard BIOS. (Your last GB of RAM needs to be relocated to above 4GB)

Also, which stepping is the AMD 64 3500+? AMD added memory hole support for their E stepping Opterons and I assume the same goes for the regular Athlon 64 line of CPUs. (it is still possible to remap, but requires a little more effort from the motherboard guys)

How much memory does http://memtest86.com/ see? (it uses a scaled down Linux kernel as I recall)

 

[seanp789]

go into bios, there should be a 4G memory remap function you need activated. You will need a recent version of bios