Timings for Twin2X2048 PC6400 and P5N-E SLI

[waldo15]

I have two sets of Twin2x1024 PC6400 (for 4GB total). Currently I am only using 2GB with 5-5-5-12, 2T @ 1.9V as suggested by Corsair because that config is the only thing stable at 800MHz

 

My question here comes when trying to have the 4GB in my MoBo running at 800MHz. If I install the 4 sticks I'll never boot to Windows, sometimes I won't even POST. So after much struggling and internet browsing I came to terms that my P5N-E SLI motherboard will not let me do anything fun with the Unlinked FSB option so I can achieve independent frequencies on the memory bus and the CPU. If I want to have 4GB of RAM in the system I have to set the clocks to linked or have some even divider values in order for it to even boot.

 

Given the above limitation, I have only a couple of options:

 

- My CPU is stable up to 3GHz. Using a linked clock approach, this gives me a 750MHz maximum speed in the memory bus. Are there lower timings recommended for this memory running that "slow"? I am completely noob at memory OC.

 

- The other option that I have seen suggested in these forums is to run the 4GB at 667MHz. Doing that what timings are then recommended?

 

[EDIT: I forgot to mention that I have "memtested" each stick independently and they are all OK]

 

[EDIT 2: My bad! I have TWIN2X1024 instead of 2048!]

[RAM GUY]

For any other settings than the tested settings you would need to test and see what the modules, and the system are capable of. I would try 4-4-4-12 if you run the memory at 667MHz, however it may or may not be stable you just have to test and see. With 4 modules in a system there is 2 times as much loading on the memory controller and you may need to overclock the board in order to get all four modules running at 800MHz. You can usually do this by increasing NB voltage to 1.45v, however this is overclocking your motherboard and you must do this at your own risk.