I'm using the Cat 3.9 and they're the best drivers I've used thus far, I haven't tried out the Cat 3.10 but I don't see a reason to upgrade yet. Maybe you should downgrade to 3.9 or try the Omega ones.
Is that 512 megs of ram 1 or two strips?
Also, I don't think it'd hurt to check this thread out either
http://www.techimo.com/forum/showthr...threadid=53409