ASROCK MB, mixed memory size modules and Windows XP

[kaktus]

Hi guys.

I have Asrock 939Dual-SATA2 motherboard (ASRock > Products > 939Dual-SATA2) with Athlon 3500+ 64-bit processor and with 2 modules of RAM memory each of 1 GB size (2 GB's in total). I tried to install two more RAM modules of 512 MB each (same Kingston brand and same speed as other two 1 GB modules) in other two black memory slots so it can work in Dual Channel mode.

Starting goes fine, BIOS recognizes 3 GB's of RAM memory (DRAM) and it operates in Dual Channel mode.

Problem is that Windows XP (SP 3) in Control Panel->System reports there are only 2 GB's of RAM memory instead of 3 GB's.

Can someone please give some advice on how to make Windows XP recognizes all 3 GB's of RAM memory I tried all modules combination?

Thanks in advance.

 

[BoBBYI986]

how much physical memory does it say you have in task manager?

 

[kaktus]

Task manager says it has 2 GB although BIOS reports otherwise.

Anyway, I was reading a lot on internet about this issue (this page for example speaks about similar problem: 3gb Ram Installed, Pc Recognized only 2gb?? - CNET Desktops Forums) and decided to try "/3GB" switch in boot.ini, but Windows still reports machine has only 2 GB of RAM memory.

 

[BoBBYI986]

do you have onboard gpu?

 

[kaktus]

No, if you maybe thought integrated vga and sepatrated vga memory would take memory and show it like is. This graphics card I have (ATI Radeon X1600) has 512 MB though.

So for now, "/3GB" switch is still there, windows still reports only 2 GB in system... at least it works.

Dunno what else to try to fix this (if it needs fixing).