Here was my output fwiw. GTX 480

C:\miners\rpcminer nvopt>rpcminer-mod-cuda.exe -url=api.bitcoin.cz:8332 -user=user -password=password -gpugrid=512 -gputhreads=480 -gpu=0
Client will start 1 miner threads
Work will be refreshed every 4000 ms
2 GPU GUDA device(s) found
CUDA initialized
Search Configuration for gpu named: GeForce GTX 480
Your device:
   - 15 streaming multiprocessors (SM)
   - can run sm version 200
   - bitcoin miner is optimized for 3 gpugrids per SM
   - max value for gpugrid parameter is 65535
max nonce 3FFFFFFF
Done allocating CUDA resources for (512,256)
iterations on gpu=32 blocks=512 threads=256
Iterations: 255,hashs per iteration 15994212185991544832
Target = 00000000ffffffffffffffffffffffffffffffffffffffffffffffffffffff
Found nonce 364CFF6C
2013-04-08 07:11:01 Found Hash!
Hashs found: 1
Sending to server: {"method":"getwork","params":["000000029bddf49cc3f72f75bf4552
d589df0fb9ec95184c247082e00000009200000000ffb19deae961efc905812ff5b1fcf69ec34f2 7
c9d0ba4194749c538e3ceb2ca751626d7e1a022fbe6cff4c3600000080000000000000000000000 0
000000000000000000000000000000000000000000000000000000000080020000"],"id":1}
Server sent: {"result": true, "id": "1", "error": null}
Found nonce AE9CEA4
2013-04-08 07:11:03 Found Hash!
Hashs found: 2
Sending to server: {"method":"getwork","params":["000000029bddf49cc3f72f75bf4552
d589df0fb9ec95184c247082e000000092000000000c048fe68ab3317714aaee783c242a630feb0 1
86961ef159df4949318f8688e051626d851a022fbea4cee90a00000080000000000000000000000 0
000000000000000000000000000000000000000000000000000000000080020000"],"id":1}
Server sent: {"result": true, "id": "1", "error": null}
137694 khash/s