you should match your ram, and AMD processors like only 2 sticks. If you have single sided ram you can use 4 without issue usually.
Originally Posted by Cyant
For dual channel you will need another pair of matched ram, they dont have to be like the first 2x2GB pair, it can be 2x512, 2x1Gb etc... Speed and timming wise it,s not important but remember all the sticks can only go as fast as the slowest stick in the lot.