does ram really matter for games?

Im building a pc online and it says 4 GB ram is only used properly on 64 bit operating systems.
Does it mean that if i get 2 GB ram that games will lag?

No not at all...
If you have a 32 bit system, only 3.31gb of ram will be utilised. the other 0.69gb will be useless.

More accurately, a computer with a 32bit operating system can only address 4GB of ram, including ram on the graphics card. Anything above 4GB will not be visible to the operating system, but if the hardware is 64bit, can be used for storing hardware information by the bios.

I would agree that that would be far more accurate than what I said.

I'm no PC guru but I don't think I have ever seen any game besides Dragon Age: Origins recommend over 2G of RAM.

Replying to #5

I think stirgo1212 meant that as an example. :)