F2-6400CL5D on EVGA nForce 680i SLI system

[sdkeller]

I just bought a RAM upgrade for my EVGA nForce 680i SLI (122-CK-NF68) motherboard. I purchased two 1GB chips of G.Skill DDR2800/PC2-6400 (F2-6400CL5D) chips from NewEgg. Today when I installed the chips my system, it would not boot (I get power but it doesn?t get through POST and I?m not getting any beep codes). I do not have another computer to test them in so I?m not sure if they are dead or if I have a compatibility issue with my system.

I currently have 2 - 1GB Corsair XMS (CM2X1024-6400C4) chips installed and when I put the new G.Skill chips in my system it will not boot up. I thought maybe that they were incompatible with the Corsair?s so I tried to take them out and just boot it with the new G.Skill chips but the result is the same.

All the specs are the same except for the timings. The Corsair?s are CL4-4-4-12 and the new G.Skill?s are CL5-5-5-15. In my BIOS under the memory timing settings, I have it set to "optimal".

Am I having a compatibility issue or do you think that I have a problem with the new RAM chips?

Thanks for any help in advance

[Tradesman]

Try with just the new sticks in slots 1-3 from the CPU. If you can get to BIOS set the timings manually as well as the voltage and the CR to 2T. If you can't get to the BIOS try with each stick individually in slot 1, if 1 works and the other doesn't then may have a bad stick.

[sdkeller]

Thanks for the reply. If I manually enter the timings for the G.Skill's will the Corsair's still work?

[Tradesman]

Any time you mix sets, even of the same model, it can be problematic. Here your mixing different sets and different brands, to try I'd go with the Corsirs in slots 1-3, the GSkill in 2-4, set the timings to 5-5-5-15, CR to 2T, and set the DRAM voltage to whichever set takes as the highest, if they are stable can try lowering the DRAM voltage a little at a time

[sdkeller]

Thank you Tradesman. I reset my BIOS and took out the Corsair's and put the G.SKill's in the slots 1 and 3, booted up and went into the BIOS to verify they were reading right, then I shutdown and installed the Corsair's back into 1 and 3 and the G.Skill's into 2 and 4 and everything is working now. It's been so long since I've been in my BIOS that I forgot that I had some OC settings set in there.

Thanks again.

[Tradesman]

Whoooooooooo!!!! Been awhile since I've been in the BIOS on one of these myself. I built some killer gaming rigs on the 680I, mainly I used the Asus Strikers and the XFX 680Is, but it's been awile and mixing DRAM on them was fairly tricky, glad the old noggin still has some of that stuff stored away Have fun!