dystieguy :
Traciatim :
Will you actually notice, not really all that much. You lose essentially half your bandwidth by not doing dual channel memory though which could be quite measurable in certain situations.
will i notice it while gaming?
Not very likely, but if you machine supports dual channel you should probably just go with the 4x2. Mainly it would probably be more impactful to memory intesnive tasks like if you were playing around in Adobe After Effects or something, but just to ensure the best performance you want to stick with the fastest configuration you support.