Can 4gb 1600mhz ram runs with 2gb 1333 mhz ram on h61m ds2 mobo rev 2.2. I have 2gb 1333 mhz ram installed in my mobo and my uncle gave me 4gb ram 1600mhz, can both runs together..?
since you already have the other memory stick in your hand, it takes less time for you to physically try it and see if it'll work than for us to come up with possible scenarios. the proof will be in the pudding!
nothing permanent (obviously you're doing this after shutting down and unplugging the computer). if it doesn't work you can always remove one of the sticks and keep either the original 2G or the "new" 4G.