not directly. but it can lower clock speeds on the ram, and null dual channeling or cause general instability depending on the pairing.. not often that it happens but. it's possible..
If you're not ocing you prob won't notice a diff.
just make sure your mobo can handle two sticks of memory at the full speed.. I learned the hard way that most 754 mobos don't do this. and underclock 400 ram to 333 auto with 2 sticks.
and if you have 939 amd 64 or you have a pentium 4 board that supports dual channel., you should get two very similar if not identical sticks of ram for best performance/compatability.
and if you're allready running dual channel I think you have to Upgrade both sticks at once I could be wrong however.
Sig removed due to size. Please read the rules before adding your compliant sig. SigSanta