Gigabyte MA770T-UD3P DIMM SLOT 2 and 4 not working

Have you set the memory voltage correctly to 1.5v?
Try to increase memory voltage, relax the timings, increase northbridge voltage.
Use the most recent bios.

Your setup won't allow for dual channel RAM operation. Your CPU only has a dual channel RAM controller. You should be using an even number of RAM sticks for optimal performance. Running three sticks of RAM on a system that's not designed for that is asking for trouble.

Look in your owners manual. Nowhere will you find mention of how to set up your system with three sticks of RAM.

http://america.giga-byte.com/FileList/Manual/mb_manual_...
Page 16.

Gigabyte messed up the manual. The explanation correctly says to use 1 and 3 or 2 and 4 but the chart incorrectly shows 1 and 2 or 3 and 4.

In any case, two sticks in 1 and 3 or two sticks in 2 and 4 or four sticks with all 4 slots full are the only combinations that will work.

That's some good advice, I tried all of that except for increasing northbridge voltage but unfortunately slot 2 and 4 do not work. And 1.6 volt is the lowest I can manually set my DRAM at. I never tweaked the NB voltage and dont know how far is too much so I'll leave that alone for now.

Plus, according to speedfan, my northbridge is at 80 degrees even when the pc is idling (rest of cpu, video card are cool though, maybe its a sensor problem). Still I don't want to take a chance when its that hot to begin with.

For fun I decided to memtest all the 3 sticks, 2 sticks passed, 1 stick failed the memtest, but at least it could boot.



Ah I see, thanks for the info. I tried to put 1 stick only and it failed to boot in slot 2 or 4, but I never tried both of 2 and 4 at the same time.

However, seeing how one of the 3 sticks has errors in memtest, I think I'll just leave the 2 sticks in slots 1-3 for now, if I need to fill in the 4 banks one day, I'll transfer the 1-3 to 2-4 first before buying.

But the problem is that 1-3 is supposed to give me dual channel, which is does not, so I suspect that this mobo has some kind of defect.



Yeah that's true, but in my older asus mobo with a 939 socket I could fill 3 slots out of 4, no dual channel but at least it worked in single channel, so I decided to give that a try.

Oh well, this gigabyte mobo had a high average rating on newegg, so I decided to try my luck. Some people had 2 mobo DOA, luckily that is not my case. Some reported that the northbridge is very hot, and mine is as well, at 80 degrees on idle even when my 955 cpu sits at 29-30 degrees, temp1 and temp2 in speedfan at 33 degrees and 39 respectively.

I would bet that is a bad reading or sensor, not a real temperature.