well..I mean I have mixed different brand of RAMs before and they worked fine, I know it's always best to go with a kit, but i don't want to just throw away my current 4GB.
I'm not doing any overclocking stuff(I never overclock with mixed RAMs),i'm using the computer mainly for VMs, and some gaming(FSX, GTA IV etc.), where the actual amount of RAM is more important than the speed I suppose. I just want to make sure if this command rate will make a difference in stability. After all they are the same voltage and same timings.