>I was using one in a C610 for a while, and it worked perfectly.  The 
>performance of the 40Mhz Centris 610 was about the same as the 
>overclocked 40MHz Centris/Quadra 650 that I'm using now.  I figured that 
>the Sonnet card would be a slower than a "real" 40MHz machine, since it 
>is a clock-doubling card, but the difference was minimal.  If anyone 
>cares, I can dig out the Speedometer results.....

My results on C610 is about the same as a 33MHz Q630, although video was 
slower.

Jeff