For those interested in the Radeon R9 270 on Linux, Kamil Páral of Red Hat shared his views on his blog and it covers a lot about issues encountered with both drivers when using the Fedora desktop day-to-day with this newer graphics processor.
Some takeaways for the open-source driver include DPM needing to be manually enabled (changed in Linux 3.13), GTK primitives being "super slow", and the fan speed being higher than with the Catalyst driver.
Notes about the Catalyst driver is that the binary blob is no longer in RPMFusion, GNOME doesn't work with Catalyst in Fedora 20, alt-tab switching doesn't work right, video overlays don't work with Totem, and you can't control your desktop over VNC.
Kamil Páral also ran some benchmarks using the Phoronix Test Suite
, of course. The Red Hat / Fedora QA developer had to say, "I was looking for some automated way of doing it and I’ve found Phoronix Test Suite. It’s a neat piece of software, packaged in Fedora, and allowed me to simply (in an automated fashion) run a series of tests and even drew graphs of the results for me. It’s simple to operate and I really recommend it."
The conclusion drawn was, "The situation is far from perfect. I really understand why Steam survey shows only 1% of Linux players in its user base. It’s hard to play in Linux with such graphical drivers. I bought an AMD card because I wanted to support them in releasing hardware documentation and hiring opensource driver developers (they do both, same as Intel, and unlike Nvidia). Nevertheless after my week-long experience (maybe I should say misery?) I really considered swapping the card for Nvidia GeForce GTX 660 (same price, same performance). Still, I’m reluctant to do it. I had bad experience with binary nvidia driver in the past, and I have had utterly abysmal experience with nouveau driver in recent years."