Can run 4gig DDR2 1066 but not 8gigs

[tycho76]

Hi,

I recently built my own machine, with the specs as such:

Model of the motherboard: MSI P43 Neo-F LGA 775 Intel P43 ATX Intel Motherboard
Model of the memory: 4x G.SKILL 2GB 240-Pin DDR2 SDRAM DDR2 1066 (PC2 8500) Dual Channel Kit Desktop Memory Model F2-8500CL5D-4GBPK
Model of the CPU: Intel Core2 Quad Q9400 2.66GHz 6MB L2 Cache LGA 775 95W Quad-Core Processor

I first had all 8gigs installed, and when starting the computer there was no display at all and it would not run. I switched to only 4gigs, and the machine runs fine. How can I configure my machine to allow all 8gigs?

Please let me know if you require any more information, thanks.

[Tradesman]

Have you tried running each stick individually to ensure each is a good stick. Also what's you're OS, if it's not 64 bit it could be the cause. What FSB are you running?

At stock FSB you'll want to set the timing manually at 5-5-5-15, 2 volts and 2T command rate. Will probably have to raise tRFC to between 68-74 in the advanced RAM timings and might possibly have to raise the NB voltage a bit.