System crash when I have 1 x 512 mb, 1 x 512 mb, and 1 x 256 mb on 3 slot KT400a mobo

[aphextwin2050]

Hello
I have a KT 400 A, gigabyte 7va x a motherboard.
I have no problems when i have it configured to
1 x 512
1 x 256

or
1 x 512
1 x 512.

but when i use
1 x 512
1 x 512
1 x 256
windows boots up but it eventually crashes.
I want to use that extra 256 , is this a problem on my motherboard?
or is it some issues with DDR?
thanks!
jon

 

[Vette73]

Check for a Bios update. Also the more slabs or ram you run, the more likely the chance it will not work.

Just use teh 2 512mg. The extra 256mg will not really help.

 

[Peter]

What kind of Windows is it?

Besides, when the electrical load on the RAM bus increases, you might need to back down on the timings, maybe even on the RAM clock. This is a well specified fact, common to all chipsets and boards.

 

[InlineFive]

Check your motherboard manual for memory settings. Some motherboards don't like anything except single-sided memory in the last slot.

-Por