Crucial Memory Upgrade question

I made my own machine about 8 months ago (thanks in huge part to the help from visiting the forums here) and when I did, I included 512mb of DDR Crucial PC-3200 memory in 2 256mb sticks.

Now that it's 8 months later, I'd like to upgrade to a full gig of memory, but my question is this:
My Epox 8RDA3+ motherboard has 3 memory slots. If I leave the current 2 sticks in and insert a stick of 512 into the third, will that effect performance or create any bottlenecks as opposed to having 2 sticks of 512 in 2 slots and leaving the 3rd empty?

The Epox should run just fine in dual-channel mode if you put the larger (512MB) stick in the single slot, and the other 2 x256 in the two slots that are close together. How this compares to 2 x 512? I can't say for sure, but I doubt any difference would be that significant. The only real way to tell would be to run benchmarks, and you would need a 2 x 512 set if sticks to do that. Got any you can borrow?

No I don't, unfortunately, but it's good to know that the difference would be minimal. Thanks for your input!

There should be absolutely no loss of performance. You can run fine with 3 sticks in dual channel. That Crucial is good stuff, too.