Hi. I have a P5B Deluxe board that I assembled into a PC two years ago. I had 2x1 GB or Corsair DDR2-800C4 and it worked just fine.
I just bought another twin pair of Corsair DDR2-800C4 but the PC doesn't boot up. It either remains black with no activity, or a splash Azuz image shows up but freezed. I managed to make it work with 3 sticks but not with the four.
Sometimes it tells me during start up that my "overclocking sets are wrong" or something like that and it doesn't go past that. I did have two profiles saved on my board, one of them an overclock profile. I now have the bios set for depault and I have updated the BIOS because I read that some memmory problems had been solved with the latest versions.
Maybe there is a problem with my saved profiles? I have now both saved with default settings because I cannot erase the profiles. Do I need to clear the CMOS or something like that?
Check your memory specs because it is likely to be a voltage issue.
If it is this stuff for example: http://www.corsair.com/_datasheets/TWIN2X2048-6400C4.pd...
you will need to manually set the vdimm to 2.1v to get all four sticks to work.
... so put 2 sticks in, set the voltage, then put the next 2 in...
The other thing to try is upping the voltage on the northbridge. This is normally called NB voltage on Asus boards. Not sure what the default voltage is for a 965 chipset - think its around 1.25v, but try upping this in increments up to about 1.35v and see if you have any joy. Keep the ram volts at 2.1v.