I have a 4870 and can't seem to get OpenCL to work with it. I downloaded the latest drivers and installed the AMD APP SDK but when I run GPU Caps Viewer I can only see my processor. I'm not sure what to try next. I've searched the web and tried getting help on AMD's forums, but with no luck (a poster there stated that OpenCL's not supported on the 4870, but I see that others on this forum are mining with the cards, so I'm not sure that's correct).
If you've had this problem or have an idea of what I'm doing wrong, I'd appreciate the help! Let me know what additional information I should provide and I'll do so. Alternatively, if there are miners that don't require OpenCL I'd be interested in hearing about them.
Thanks for the help!
(I should have added that I read the post here http://forum.bitcoin.org/index.php?topic=19122.0
that suggested uninstalling and reinstalling the latest Catalyst pack, which I did, but I'm having the same problem.)