Jump to content
Corsair Community

Corsair XMS DDR2 +Crosshair +Phenom


Recommended Posts

Not sure I have a problem, but my system only ever detects 3.5Gb of memory when I have 4xCorsair XMS DDR2 1g sticks installed.


I realize from other posts I've read here that I needed to drop the speed of the DRAM from 800Mhz to 667Mhz . . .which I've done, and ran Memtest CD for 4 passes with out error. System is stable as well, just pondering where the other 1/2GB of ram went to :biggrin:


BIOS reports 4096MB installed, and 3583MB usable(this is what vista detects also-3583MB). I thought I remember reading somewhere that each SLI slot used takes up 256MB system memory, which would put me exactly where I am. I just want to make certain I'm not missing anything


BIOS settings:

Memory Timing


SLI-Ready Memory: High Performance (Optimal and Disabled work and pass Memtest as well)

tCL: 4

tRCD: 4

tRP: 4

tRAS: 12

Width of DRAM Interface: 64-bit

1T/2T Memory Timing: 2T

Channel A Clock Skew: Normal

Channel B Clock Skew: Normal

DDR2 Voltage Control: 2.1v


Advanced Memory Settings


tRC: Auto

tWR: Auto

tRRD: Auto

tRWT: Auto

tWTR: Auto

tRTP: Auto

tWRRD: Auto

tWRWR: Auto

tRDRD: Auto

tREF: Auto

tRFC: Auto

DRAM Termination: Auto

Max Async Latency: Auto

R/W Que Bypass: Auto

Dynamic Idle Cycle Counter: Auto

Idle Cycle Limit: Auto

DCQ Bypass Maximum: Auto

DRAM Burst Length: 8 (QW) - 64bit

Dram Bank Interleaving: Enabled

Memory Hole Remapping: Enabled

all else set to Auto


Also to note, the 9600 Phenom runs at 2.3Ghz, but I run it stable @ 2.6Ghz(226x11.5=2.599). Only option in Bios is to change the DEC, the option to change the multiplier is grayed out, so I can't run at anything other than x11.5 multiplier.


If I'm missing something here please let me know, or let me know all my settings are as they should be.


thanks in advance!

Link to comment
Share on other sites

This is an OS problem. You might wish to contact Microsoft with it but I have heard that the SP release for VISTA will correct this issue. Since the BIOS reports correctly you can be certain that the hardware of board chipset and memory are correctly working.
Link to comment
Share on other sites

  • 3 weeks later...

After loading bios v1001 and Vista SP 1 my system now detects the full 4GB, both in the bios, and in Vista.


I did have bios v906 running for a bout a week, but it made do difference.


Unfortunately I did not check between updates so, I'm not sure which one did the trick or if it was the combo. In any event my system is stable, and running faster than ever.


thanks once again for all the help!

Link to comment
Share on other sites


This topic is now archived and is closed to further replies.

  • Create New...