Fighting my ATI

First of all, the Cafe is not a good place to post questions of a technical nature.  You will be much more likely to get responses if you post in Crunchers Corner for example.  If you like, I can shift the thread there with your permission.

fglrx is deprecated these days.  To use that old driver you need to be using an old version of xorg - I use 1.17.4.  If you happen to be using 1.18.x, fglrx will not be compatible.  Is your OS 32bit or 64bit?

I have a HD7950 working very nicely with fglrx.  The distro I use dates back to May 2014.  If you are prepared to run an old distro and can get the packages you need for OpenCL you should be OK.  I know nothing about Mint or Ubuntu (never used them) so can't help you on that score.

I think your best bet would be to go to the Mint forums and ask specific questions there about what driver to use to get OpenCL compute capability, particularly if going back to an older version where fglrx works out of the box is not an option.  I don't know anything about Mint 17.2 but if it is old enough to use fglrx, perhaps you are just missing the OpenCL libs?

I just decided to look at your computers list.  The last contact log for your machine with the tahiti GPU (far RH column) contains the line,

2017-05-06 20:56:36.3959 [PID=457 ] [version] ATI device (or driver) doesn't support OpenCL

which implies that the driver is OK and that you are missing the OpenCL libs.  Just find that package and install it.  The above message is what you get if you don't have the libs correctly installed.