I have just order my new rig parts:
B75 Ivy Bridge cheapest mobo I found
7850 1gb Club 3D
OCZ modxstream 500W PSU
at the moment i have apacer ddr3 1333mhz 2x2gb ram. I will be okay with this? Or I should pick something better ( corsair 2x4gb? ) That make any diference for e.g. BattleField3 FPS ? My budget is low! I guess RAM doesnt make big influence on system... thats why I Want to stay with old apacer 2x2gb 1333mhz cause have no money, but dunno yet. Give me advice where should i go with this problem.
You don't have a problem. As long as they're compatible and work, you don't have to worry about the WEI score. My laptop with 4GB of memory has the same score. Here's what it says:
"The scores currently range from 1.0 to 7.9. The Windows Experience Index is designed to accommodate advances in computer technology. As hardware speed and performance improve, higher score ranges will be enabled. The standards for each level of the index generally stay the same. However, in some cases, new tests might be developed that can result in lower scores."