Today, when I installed VS2008 SP1 on my office PC, I noticed that one of my cores are totally captured by mscorsvw.exe. A quick google search reveled that this service is used to precompile .NET assemblies. If you ever encounter this, then run
ngen.exe executequeueditems, this will compile all the queued assemblies, followed by a restart. After reboot, your CPU will return to normal. Hoooray.
Reference: David Natario’s WebLog