4gb ddr3 and 8gb ddr3 sticks at the same time?

[dragos popa]

I'm just asking because I have a amd apu and ive heard that dual channel is way better for it. But is it possible to have 2 sticks of the same speed but different size in my motherboard at the same time? my motherboard is a asus a68hm-plus

 

[Phillip Corcoran]

Dual Channel won't work if the two sticks are not the same capacity, and ideally they should be bought as a "matched pair" so they are identical in every respect to ensure that they will work when used together.

But at a minimum, the two sticks must be the same capacity for dual channel to work.

Dual channel will always perform better than single channel, regardless of what CPU/APU is installed.