I have no idea which of these to get because of difference in price. Could you guys give me some detail information about them? Like do they run faster or something? What differences do they make?
Here are the two RAM items I am looking into: http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Okay, basically the difference is the first DIMM runs at a faster speed of 1600mhz as apposed to 1333mhz of the second DIMM. So to answer your question the first DIMM runs faster. However, speed doesn not really matter that much with RAM for the average PC user as the performance difference is negligable.
As far as compatibility goes, I would say that providing your processor supports 1600mhz RAM then both sets will work fine. But be aware that 4gb of RAM will only show up as 3.2gb on a 32bit OS. If you have a 64bit OS then you can use the full 4gb. =)