Blue RAM slots causes not to boot

Hi,

I got Gigabyte GA-MA790XT-UD4P mobo, with four memory slots (2 blue and 2 white). I've been using two 2GB memory sticks on white slots and everything has been working fine. Now i bought two additional 2GB sticks and when adding one stick to blue slot, mobo just keeps beeping and screen stays black. Even if i remove all other sticks and put just one to a blue slot, it wont boot. Memory sticks are Team Group 2GB Elite, DDR3 1333MHz (PC3-10660) CL9.

So whats wrong with the blue slots? Manual doesn't say whats the difference between blue and white slots, i'm thinking it has something to do with dual channel?

You have to install them in pairs. Installing just one won't work. the difference between the blue and white slots are different channels. as long as you put an identical module in each blue and a matching pair in the white it should work. The pair in the white do not have to match the pair in the blue.

1-2 should match and 3-4 should match. if it still doesn't work try only using 2 sticks at a time to figure out if one of them is bad.

I just answered a question identical to this (no answer yet) and it was also a Gigabyte motherboard.

Since you've apparently verified all RAM sticks work (but not at the same time) that seems to indicate that the RAM works.

I have only two things to suggest at this time:
1) run Memtest on each pair (in the white slots)

2) BIOS update. your RAM may not yet be properly identified so it's using generic timings which may pose issues with fours sticks of RAM. I would not have thought that it would case it not to boot though.

Anyway, check for a BIOS firmware update.

Summary:
1) Memtest to verify RAM
2) BIOS update
3) unknown motherboard issue?

I ran memtest last night and it found 1200 errors on two of the sticks during 9h period. They've been working fine though, no BSOD:s or crashes whatsoever (on white slots ofcourse).

The other 2 sticks came out with no errors.

BIOS is up to date. I've contacted Gigabyte tech support for this. Im starting to think its faulty slots on the mobo.

It's always unganged, even when i switched to ganged from bios it said unganged on memory check and with CPU-Z.