Explain memory speeds...

[Shure]

What kind of difference does the speed of memory make such as these for example:
G.Skill 2GB DDR2 GA PC2-5400
G.Skill 2GB DDR2 PK PC2-6400

To a "standard" (Non-overclocker) user is there a difference?

 

[Pulseammo]

As long as the memory can run at the rated speed for the platform, then nothing. Perhaps at a later time the manufacture (intel or amd) may up the speed on the platform (like how athlons went from 266 to 333 to 400mhz) in which case it may give the RAM a longer life span.

But in terms of performance now, there is no difference. With one speed of ram there is a sync issue though that causes a very slight performance decrease. I cant remember what rating it was but I think its PC6400 that does that unless you are overclocking with it.