It will not work very quickly.....!!!!!!!!!

1. bitcoin is Sha256(Sha256(x)), where x is the data+nonce
2. even if you were to implement this card, you would have to get the data from the card and then send it back in again!!!!
Then when it came out again, you would need to compare the  ass end for a row of zeros

So even with the fastest fucking CPU on market.. it is STILL going to be slower than even a shitty FPGA, why?
Well because an FPGA can collapse down 'Sha256(Sha256(x)) top bits =0' into one fucking clock cycle.....

Where as your setup is going to require several syncronised clock cycles to do the above.......(certainly to get the data over PCI)
 AND your main nonce increment is going to be OUTSIDE the high-speed logic & inside your overpowered CPU.....


Go learn a little more about bitcoin and how it works.....