Corsair XMS2 and Gigabyte GA-MA790FX-DS5

Blaen

Blaen

Blaen

Associate
Joined
12 Apr 2008
Posts
9
I've recently setup a new build with the following memory and motherboard:

Corsair 4GB Kit (2x2GB) DDR2 800MHz/PC2-6400 XMS2 Memory Non-ECC Unbuffered CL4(4-4-4-12)

Gigabyte GA-MA790FX-DS5 790FX

Although I've not overclocked before I need some advice. The SPD for the memory within the BIOS is showing timings of 5-5-5-18 rather than those stated for the XMS. Firstly can anyone provide me with detailed manual timings that would need to be used for this MoBo (latest BIOS release) so I can run the memory as intended please?

Secondly the POST shows the memory as 'unganged' mode. I'm using slots 2 and 4 which, as far as I can tell should enable dual channel mode (ganged?). Within the BIOS there is an option for 'Ganged' or 'unganged' but neither actually change the POST from unganged. Am I missing something, I've tried slots 3 and 4 rather than 2 and 4 with the same effect. I cannot use slot 1 because the scythe cooler blocks access.
 
Last edited:
Welcome to the forums! Its probably best to use the first slot if you can move that cooler around a bit. Also can you not just tighten the timings up to 4-4-4-12 manually. If the RAM is rated at that, it should manage those timings.
 
Previously on older MoBo's that seemed straight forward, but in addition to the first 4 listed timings there are more shown in the BIOS. This is why I need advice, I'm not sure if they should be changed or not?

As for the cooler I'm afraid there's no chance it can be moved to free up slot 1. But according to the MoBo manual, 1+3, 2+4 or 1+2+3+4 should, if using matched pairs, all work in dual channel mode. But I still cant get POST to show anything other than unganged....
 
I've now solved the dual-mode. In error in the manual, Gigabyte list 1+3, 2+4 for dual channel modes.

On their website and in practice if you use 1+2 or 3+4 you get dual channel. I also now understand what the "ganged" or "unganged" means. In "ganged" mode, the CPU has standard bandwidth. In "Unganged" mode, each full channel has full bandwidth, so if you have 4 modules installed "unganged" mode gives much more bandwidth between CPU and memory than "ganged" would, however with only 2 modules installed in dual-channel mode it makes no difference.

I'm still trying to work out all the specific memory settings that become available under manual mode however.
 
Right have now tried changing the settings to 4-4-4-12 manually, the voltage by EPP is 2.16 (I think) so hasn't been changed. However with these settings the PC cannot boot and automatically reverts to 5-5-5-18. Anyone got any tips for me please?
 
Are you trying to use EPP settings AND changing the timings manually? If so, clear the CMOS, and set the timings manually to 4,4,4,12 and set the voltage manually to 2.1v. Leave the other memory timings at the MOBO defaults.
 
So basically disable EPP and that should allow the timings to be set along with manually configuring the voltage? I'll give it a go when I get home from work and see what happens. I think the base voltage the MoBo uses is 1.80v so I'll boost it manually by 0.3.
 
Last edited:
Ok I've tried everything I can think of but it will not POST once memory timings have been changed to 4-4-4-12 even though the memory should support this.

Other components of import I'm running are:
PSU - Antec Phantom 500
CPU - Phenom 9600 BE
MoBo - Gigabyte GA-MA790FX-DS5
- BIOS: F5 release
GPU - MSI 8600GT

I would really like to run the memory at the speed it is supposed to be able to, but am at a loss to work out what I'm doing wrong.

I've tried disabling EPP completely and manually setting the voltage to 2.10v then the timings to 4-4-4-12 but every time I do it, the MoBo refuses to POST and resets the BIOS to 5-5-5-18.
 
You must log in or register to reply here.
Back
Top Bottom