We're monitoring things, and looking how we can squeeze out the last little bit of performance out of the main server. We may need ot throw more memory into it, but for the moment we are just trying to learn what causes the biggest performance hits and trying to iron them out.
One way to improve performace is if you do not need email notifications for your topics is to go to your profile and turn them off. The email server gets really battered.
Oh, and yes, as Julian mentioned, we do get an attack now and again, which slows the whole thing down too!
Trystan