GA-MA790X-UD4P, can only use dimms 1 & 2??

[jton219]

I have a MA790X-UD4P (ddr2 version). I can only boot a 2x2gb set of g skill mem in dimm slots 1 and 2.

i've tried 3 and 4, 1 and 3, 2 and 4, and i cant get to the post screen. any ideas what is wrong??

I asked a g skill rep about dimm placement and unganged settings and he said its best to have 1 stick in channel 1(dimm 1 or 2) and the other in channel 2(dimm 3 or 4). I think when in unganged mode, each 64bit on die mem controller of a phenom II chip can only access one of the channels. i could be very wrong. not sure here

Bios is FB, which i think is the latest.

[ReverendMaynard]

it's definitely the first two slots.

[EvilBlitz]

I have the exact same board with 2x2gb of DDR2 900 Gskill. Running at rated specs at 900mhz in slots 3 and 4(dimms are too tall too go in 1 and 2, blocked by thermalright extreme). Works perfectly fine.
Bios is F7.

Ram timings are CL 4 tRCD 4, tRP 4, tRAS 15, tRC 26 CR 2T.

My rams recommended settings are for a tRAS of 12 and a tRC of 40, but the bios cant go above 26 for tRC. So I left tRAS at 15 instead of 12 and put tRC at 40. Seems to work fine, have not had any crashes.

Are you overclocking in any way?

[jton219]

I have the mem at 800 4-4-4-12 1T..I didnt think ddr2 800 could run at 1T..but its been working fine. Not one blue screen.

Cpu is at 3.6 .... 240HTTx15. Its nice.

[EvilBlitz]

How come you want to put the ram in 3&4 if it works fine in 1&2? Are you upgrading to a cooler that blocks the ram slots?

[BeepBeep2]

Umm, I run my OCZ DDR2-1150 in DIMM slots 3 and 4 without issues:
http://img30.imageshack.us/img30/7874/lvplatinum11501220.png


That would be highest everest, DDR2-1220 @ 1.94v 5-5-5-15 2T

My instability may be due to the NB speed though, it was at 1.27v when I ran the bench. As for 1T, it maxes out around DDR2-900 5-4-4-12

[jton219]

I just tried 3 and 4 cause i was curious. I was using a cooler pointed up and it did cover slots 1 and 2 but the ram still fit there. One heatpipe was rubbing up against the ram heatspreader. Thats when i tried 3 and 4. No go.

i changed the cooler direction to blow out the back, and im leaving the dimms in 1 and 2. I dont want to worry about it anymore.. Hope i dont have a problem if more sticks are added though.

[BeepBeep2]

Hmm, I'm really curious as to why slots 3 and 4 dont work for you. I mean, the screenshot I posted above was of my two OCZ sticks in slots 3 and 4 in Dual Channel, unganged DDR2-1220 1.9v CAS 5-5-5-15. My DDR2 works like a charm. :/

I run a 965BE C3 though? I hope you don't have a bad board.


BTW:

Channel 1 is 1 and 3 and Channel 2 is 2 and 4 according to the manual. I don't know what the G*Skill rep was talking about.