Initially had a lot of trouble with my Sonnet G4 700 upgrade for my 9600. Spent a week of Hell swapping in/out 12 RAM sticks, PCI cards, etc.
Was about to give up but sent a last ditch email to Sonnet support. Received a message from Neal who advised removing the original TwinTurbo video card as he knew there was a conflict but it wasn't yet listed on the Sonnet site.
Bingo, once that card was removed the upgrade ran fine. Few stalls ocassionally but otherwise OK.
So, thanks to Neal they kept a customer.