You probably have too much RAM allocated to the virtual machine, for one thing (or not enough in your Mac, I would recommend having at least 2 GB). The only way for Parallels to slow down Mac applications that much is if you give the virtual machine too much RAM, or something in the virtual machine is causing excessive disk usage. Excessive CPU usage won't usually cause much Mac OS X slowdown because of OS X's multitasking ability and the fact that most Intel Macs are dual core. Also since you are having networking problems, have you tried changing the networking type from "Shared networking" to "Bridged Ethernet"?
You could use Boot Camp if you have too many problems with virtualization programs (after all, you have a $1000+ PC already, why get a $250 one?). Most Parallels users don't have the problems you are describing (my networking through Parallels has always worked just fine, and Parallels doesn't slow down my OS X applications at all).
Last edited: Sep 28, 2007