in some cases, yes.
if the ram is running asynchronously, as with the kt333
people find that 133/133 with Cas2 is better than 133/166 with cas2.5
if your running synchronously, as i think u are, its best to try it for yourself.
set all your ram timings to their hardest settings, and see how high u can go.
You're an embarrisment to nature you know that?