If you're looking at half a gig of RAM, you're clearly trying to build a pretty powerful machine. I wouldn't go generic - suck it up and shell out the fifty. You might be able to get away with the generic, but it might just give you some bizarre errors that would necessitate you returning it. Plus, you should be able to run the Crucial at "turbo" memory setting (CAS 2, 4-way bank interleave, etc.) - probably wouldn't be able to do that with generic. Again, if it were a cheapo office machine, maybe the generic would do, but I bet you want better than that.