It seems that a lot of GPU problems revolve around specific versions of drivers. Though AMD has their own support structure, you can often learn from information reported by others who fold.
20:05:16:WU00:FS01:Requesting new work unit for slot 01: READY gpu:0:Cayman [FirePro V5900 (FireGL V)] from 192.0.2.1
20:05:16:WU00:FS01:Connecting to 192.0.2.1:8080
20:05:37:WARNING:WU00:FS01:WorkServer connection failed on port 8080 trying 80
They are part way through redoing the species numbering for AMD GPUs to make them more performance based than generational. Some issues have arisen, will pass on your report.
iMac 2.8 i7 12 GB smp8, Mac Pro 2.8 quad 12 GB smp6
MacBook Pro 2.9 i7 8 GB smp3
This should (very slowly) fold. It does 64 bit (Double Precision) floating point math and supports OpenCL 1.2, the minimum requirements for F@H GPU folding.
It is 9 years old and (depending on how you count) three AMD generations back. With only 512 cores it would not be fast even if new. (80% as fast as a GT 1030?)
Folding slowly should be acceptable for some projects, but not all. I don't mind leaving that up to the project owner. The question is whether Joseph has blocked species 3 (->192.2.0.1)