I was able to download and run CUDA gpu units just fine on my mac, then i switched my video card to a GTX470 and (without changing any setting in primegrid or boinc), i get "No work available for the application you have selected. Please check your project preferences on the web site." CPU packets still work per normal, however i am unable to get any CUDA units. here's my event log to show it's loading the CUDA drivers and finds the card fine.

Fri Aug 12 16:44:19 2011 | | Starting BOINC client version 6.12.33 for x86_64-apple-darwin
Fri Aug 12 16:44:19 2011 | | log flags: file_xfer, sched_ops, task
Fri Aug 12 16:44:19 2011 | | Libraries: libcurl/7.19.7 OpenSSL/0.9.7l zlib/1.2.3 c-ares/1.6.0
Fri Aug 12 16:44:19 2011 | | Data directory: /Library/Application Support/BOINC Data
Fri Aug 12 16:44:19 2011 | | Processor: 8 GenuineIntel Intel(R) Core(TM) i7 CPU 860 @ 2.80GHz [x86 Family 6 Model 30 Stepping 5]
Fri Aug 12 16:44:19 2011 | | Processor features: FPU VME DE PSE TSC MSR PAE MCE CX8 APIC SEP MTRR PGE MCA CMOV PAT PSE36 CLFSH DS ACPI MMX FXSR SSE SSE2 SS HTT TM PBE SSE3 DTES64 MON DSCPL VMX SMX EST TM2 SSSE3 CX16 TPR PDCM SSE4.1 SSE4.2 POPCNT
Fri Aug 12 16:44:19 2011 | | OS: Mac OS X 10.6.8 (Darwin 10.8.0)
Fri Aug 12 16:44:19 2011 | | Memory: 8.00 GB physical, 42.79 GB virtual
Fri Aug 12 16:44:19 2011 | | Disk: 55.45 GB total, 42.55 GB free
Fri Aug 12 16:44:19 2011 | | Local time is UTC -4 hours
Fri Aug 12 16:44:19 2011 | | NVIDIA GPU 0: GeForce GTX 470 (driver version unknown, CUDA version 4000, compute capability 2.0, 1280MB, 1089 GFLOPS peak)
Fri Aug 12 16:44:19 2011 | PrimeGrid | URL http://www.primegrid.com/; Computer ID 214936; resource share 100
Fri Aug 12 16:44:19 2011 | PrimeGrid | General prefs: from PrimeGrid (last modified 15-Jun-2011 19:22:17)
Fri Aug 12 16:44:19 2011 | PrimeGrid | Host location: none
Fri Aug 12 16:44:19 2011 | PrimeGrid | General prefs: using your defaults
Fri Aug 12 16:44:19 2011 | | Preferences:
Fri Aug 12 16:44:19 2011 | | max memory usage when active: 4096.00MB
Fri Aug 12 16:44:19 2011 | | max memory usage when idle: 7372.80MB
Fri Aug 12 16:44:19 2011 | | max disk usage: 27.73GB
Fri Aug 12 16:44:19 2011 | | suspend work if non-BOINC CPU load exceeds 25 %
Fri Aug 12 16:44:19 2011 | | (to change preferences, visit the web site of an attached project, or select Preferences in the Manager)
Fri Aug 12 16:44:19 2011 | | Not using a proxy
Fri Aug 12 16:44:19 2011 | PrimeGrid | Restarting task pps_llr_96101366_0 using llrPPS version 609
Fri Aug 12 16:44:19 2011 | PrimeGrid | Restarting task pps_llr_96101367_0 using llrPPS version 609
Fri Aug 12 16:44:19 2011 | PrimeGrid | Restarting task pps_llr_96101321_0 using llrPPS version 609
Fri Aug 12 16:44:19 2011 | PrimeGrid | Restarting task pps_llr_96101355_0 using llrPPS version 609
Fri Aug 12 16:44:19 2011 | PrimeGrid | Restarting task pps_llr_96101097_1 using llrPPS version 609
Fri Aug 12 16:44:19 2011 | PrimeGrid | Restarting task pps_llr_96101311_1 using llrPPS version 609
Fri Aug 12 16:44:19 2011 | PrimeGrid | Restarting task LLR_SGS_95717781_1 using llrTPS version 609
Fri Aug 12 16:44:19 2011 | PrimeGrid | Restarting task LLR_SGS_95716986_1 using llrTPS version 609
Fri Aug 12 16:45:20 2011 | PrimeGrid | work fetch resumed by user
Fri Aug 12 16:45:25 2011 | PrimeGrid | Sending scheduler request: To fetch work.
Fri Aug 12 16:45:25 2011 | PrimeGrid | Requesting new tasks for NVIDIA GPU
Fri Aug 12 16:45:25 2011 | PrimeGrid | update requested by user
Fri Aug 12 16:45:27 2011 | PrimeGrid | Scheduler request completed: got 0 new tasks
Fri Aug 12 16:45:27 2011 | PrimeGrid | No work sent
Fri Aug 12 16:45:27 2011 | PrimeGrid | Message from server: No work available for the applications you have selected. Please check your project preferences on the web site.
Fri Aug 12 16:58:40 2011 | | Re-reading cc_config.xml
Fri Aug 12 16:58:40 2011 | | log flags: file_xfer, sched_ops, task
Fri Aug 12 16:58:44 2011 | PrimeGrid | Sending scheduler request: To fetch work.
Fri Aug 12 16:58:44 2011 | PrimeGrid | Requesting new tasks for NVIDIA GPU
Fri Aug 12 16:58:47 2011 | PrimeGrid | Scheduler request completed: got 0 new tasks
Fri Aug 12 16:58:47 2011 | PrimeGrid | No work sent
Fri Aug 12 16:58:47 2011 | PrimeGrid | Message from server: No work available for the applications you have selected. Please check your project preferences on the web site.