Quake 3 on AMD Dual Core Processor?

Just got a new computer loaded with Windows Vista and an AMD Athlon 64
x2 dual core processor. I was suprised how poorly Quake 3 performed
on this rig: the game seems to stutter along instead of playing
smoothly as it did on my old box.

Looking around the Internet it seems like this has something to do
with how Quake 3 gets its timing information. Windows XP apparently
has its own set of problems with dual core CPSs. Solutions mentioned
to fix this include:

1) An AMD Dual-Core Optimizer program available from AMD's site
2) Some sort of driver, also available from AMD, for fixing the
Windows XP issue.
3) A "hotfix" from Microsoft that also deals with the Windows XP
problem.

I haven't run across any mention of a Windows Vista problem with dual
core CPUs.

Given all this it seems like the only program I need to download and
install is AMD'd Dual-Core Optimizer.

Is this correct?

TIA.

Tom Young