In sync vs. out of sync?

I have some Samsung PC2700 that can hit 200 without any problems whatsoever. Due to a, 1/5 divider, though, my FSB can only hit 188, and thus I thought it would be good to run the RAM out of sync at 200 (KT400 supports it, and it's working fine)

I heard someone say, though, that running out of sync totally kills performance... is that true? I'm getting 100 more 3dmarks running at 200 vs. 185, but I tend to not trust 3DMark, not even 01.

For AMD mb, since memory and FSB are running DDR at the same clock frequency, the overall system memory bandwidth is limited by the smaller of the two. So the bandwdith is practically the same whether you run them in SYNC of ASYNC.

If it is a dual channel AMD mb, there would be some difference depending on the max fsb and max memory speed.