Simple solution is to keep the 500 in the 9600 and use the 800 in a B&W or Beige G3. On higher speed CPU's the slow memory BUS and FSB (50mhz) of the 9600 will slow it down, best bet is to go 8 x 100 in a B&W G3 which would be pretty snappy.

Sounds like you got that CPU cheap (dead) so you got a good deal.