Upgrading ram now computer crashes when playing games

[statue12]

Ive got an abit AV8 motherboard, It supports 4 gig or ram. I bought a 1gb stick of pc3200 400mhz ram to match the speed of my 512mb stick which is the same speed. When i put the both sticks in the computer it works ok on windows but when using memory intense apps or games it will restart. I know the ram isnt faulty as the both sticks will work on there own.

Any ideas
Cheers.

 

[red onion]

What slots are they in? Your MB may not like having them in dual channel config as they are not the same size. Try putting one in a different slot.

 

[statue12]

ive tried them in slot 1 and 4, 2 and 3, 1 and 2, when i put them in 2 and 3 the game actually loads and can play it for about 2 mins before it crashes, where as when they was in slot 1 and 4 it would crash as the game was loading.

cheers for the help

any more ideas