I was wondering if it was ok to mix and match ram sizes from same company and ddr3 memory right now i have 2gb X 2 of ddr3 1600mhz ram from gskill i would like to get a 8gb set 4gb X 2 same speed and same manufacturer so i have a total of 12gb would that work? Thanks.
No guarantee, but if the ram has the same voltage, and other characteristics, it is likely to work.
Current Intel cpu's seem to be more tolerant of mixed ram than in the past. Amd may not be so tolerant.
Split the ram up so you have 4gb and 2gb on each channel. That way you will still get dual channel operation.
If worst comes to worst, just use the 8gb kit.