the RAM should work, provided they are the same type of RAM. if the newer computer supports DDR2 and you have DDR, or vice versa, you would be out of luck. just make sure they're the same type and you should be good to go.
as for the video card issue, no i don't believe that would work. SLI and crossfire (for nvidia and ati cards, respectively) exists but you have to have two of the same cards. since you have one from each, i don't think anything good would come from plugging the x1600 into it. you could always try if you have a free pciE slot, but i wouldn't recommend it. just figure out which card is faster and use that one.
hope this helps
Edited by dogslikeus, 21 May 2007 - 08:16 AM.