BjorntheMan :
I currently have a GeForce GT 620 1gb, and when i go into CPU-Z and check in the memory box it says "Type DDR3". Maybe it doesnt matter?
MOBO = MOtherBOard
GPU = Graphics Processing Unit - Video Card
PSU = Power Supply Unit - PC Font
CPU = Central Processing Unit - Processor,
No, not when we're talking about GPUs tho
DDR3 or 4 is for RAM, GPUs uses GDDRx ( x being 5, in most cases ). They are complety (almost) different types of memory and don't work very alike so no there's no reason to compare both. Don't worry,
and about the claim that @snurp85 made:
It is true, recent GPUs have 3.0 PCIE, but those have backward compatibility, so whatever came before 3.0 will still work properly. The bottleneck made would be minimal as the speed between 2.0 and 3.0 isn't big. So you can rest easy with that too.