It has seemed to me that my computer had been operating slower and
slower.  I confirmed this by checking the reported CPU speed and doing
bench marking with various utilities.  The PC has a 550Mhz CPU and was
originally bench marked at 233Mhz (doesn't sound like much but it makes
a HUGE difference).  I finally (by accident traced the problem to a new
NVIDA GeForce PCI video card.  The card had to be removed to get the
mother board out and because I was changing jumper settings to get the
speed corrected to 550 Mhz, I simply left it out while testing.

When I finally got the machine running properly, the only thing left to
do was button up the case and reinstall the video card.  As soon as I
put the card in, the speed dropped to 333 Mhz.  Through trial and error
I have determined that with the card out the machine runs at 550 Mhz.
With the card in the machine runs at 233 Mhz sometimes and 333 Mhz
sometimes.

What is causing this and can it be corrected?