GeForce 9800 GX2
 

A note in case anyone has the same problem:

Yesterday I updated the drivers for my graphic card on my Vista 32 system. When I tried to run NecroVisioN today everything was shaking. It was like there was an earthquake happening. FPS was down to about 5.

I had to remove the device in Device Manager and re-install using the previous driver from file '181.22_geforce_winvista_32bit_international_whql. exe' which is stable.

Took me more than an hour of mucking about to fix this. Rolling back the driver did not work.