Issue with RAM not being usable in GIGABYTE GA-X58A-UD5

[mattg1981]

I recently purchased a GIGABYTE GA-X58A-UD5 and 12 GB G.SKILL PI Series (6 x 2GB). Build went good, but I have an issue where the mobo see's all 12gb but only 8gb are usable. When I boot into memtest, it detects all 6 sticks, but up at top says 8gb. Also in Windows 7, when i look at system properties, it says:

Installed memory (RAM): 12.0GB (8.00GB usable).

Im thinking its a BIOS setting or something, thats why I posted on this forum as opposed to RAM (since it actually see's the 6 sticks), but I havnt seen anything in the manual or online that has helped me any.

Matt

p.s. - attached some photos to show you what i mean

 

[mattg1981]

i found the issue, as you can see i had overclocked it to 4ghz .. but somewhere along the way I lost my channel C ... setting the everything back to scratch has all of them appearing again. I will have to bump my clocks up slower this time and keep an eye on this.

I assume the QPI clock might have caused this issue? ... would cranking the voltage up some bring the c channel back online?

 

[mattg1981]

it appears to be based strictly off the timings of the ram. It seems that i have 4 good sticks and 1 or 2 (2 per channel c ... either 1 or both) that cannot keep up with the timings while the RAM on the other channels can. Its not 'bad' RAM as it is hitting its advertised speeds, just that they cannot overclock as well as the other sticks.

The motherboard is then shutting that channel down and says "we know you have 12gb, only 8gb can keep up with these speeds, so we are gonna shut down channel X.