This is a bit of an odd problem I suppose, but is there anything that can be done for a dual-GPU machine that mixes OpenCL capable ATI cards with older, non-OpenCL ATI cards. For example, I am running both an HD4650 and the onboard ATI GPU (based on the HD 2xxx series) in one machine. The 4650 can do OpenCL, so it is running the PPS sieves okay. However, the onboard GPU picks up that work and errors it out in 2-3 seconds. I am not flooding the PG servers with this one since I have Collatz catching the older GPU often enough (and running for about 8 hours per work unit to keep it busy).
I suppose I could just turn off the onboard GPU since it is quite slow. However, I could see someone with 3850/3870 cards mixed with 4xxx or 5xxx cards not being quite so eager to do so...
141941*2^4299438-1 is prime!