After cataloguing GPU specifications, performance tests from various sites, reading a ton of posts on the subject, and deductively looking at marketing from Sony&AMD. My theory is that AMD's XT chips would be the best performers and most stable in Vegas.

Here is brief run down:

HD5770 - Juniper XT - Sony used to specify this a supported card in Vegas requirements back in VP11. Apple selected this card for its workstations.

HD7970 - Tahiti XT - Clearly a solid performer for not only Vegas but other apps as well. Also the same chip the w9000 uses, former flagship FirePro, and AMD demonstrated Vegas editing best/full 4K playback.

R9-290x - Hawaii XT - Also the same chip the w9100 flagship FirePro uses. Clearly the current top playback performer on Vegas.

R?-390x - Fiji XT - Rumored to be much greater performance and much lower power usage than 290x.

Is this just simple chip manufacturer binning? Just seems like the XT line is what ADM engineering is going for, and could this also then mean the most stable driver set. A driver set that is not working around limitations of manufacturing rejects rebranded as lower performance product?

Just some thoughts