Hey guys, I'm in the midst of finding parts for my first build and I don't know which is better to go with, 2x2gb of RAM or 1x4gb of RAM. If I plan on upgrading to 8gb of RAM in the future should I go with the 1x4gb that way I only use up 2 of the slots as opposed to all 4 slots? Also, how big is the performance difference between 2x2gb and 1x4gb? I plan on using this computer for primarily gaming but in the future I might do some video editing as well as I want to try my hand at making machinima.
From a performance point of view, there will be minimal difference among your options:
1) 2 x 2gb
2) 4 x 1gb
3) 1 x 4gb.
If forced to pick, I would exclude #2. It gives you no option to go 8gb w/o waste.
One problem with upgrading ram later is that you can't insure compatibility. In most cases, so long as the voltage and specs are the same, you will be fine.
But... there is no guarantee that a future ram stick will have the same build characteristics as the original; even with the same part numbers. Ram vendors can and do change their manufacturing processes. That is why ram is sold in kits; to insure compatibility.
I suggest that you find a way to get a 2 x 4gb kit up front. It will not cost that much more. Do not spend extra for faster ram or better timings. It generally does not make much of a difference in real application performance or FPS. (synthetic benchmarks shine though)