Phoronix published a review on the Sapphire Radeon R7 260X
A quote from the article:
For those in the market for an affordable mid-range graphics card that will run just fine on Ubuntu and other Linux distributions while having the choice between the open-source RadeonSI Gallium3D driver and the binary but high-performance Catalyst driver, meet the Sapphire Radeon R7 260X. Our Linux hardware review for today is looking at the Sapphire 100366L Radeon R7 260X 2GB graphics card.Sapphire Radeon R7 260X @ Phoronix
Sapphire kindly sent over the Radeon R7 260X earlier this month and it's been running great with Linux. Sapphire's Radeon R7 260X features 2GB of GDDR5 video memory, dual DVI connections, HDMI, and DisplayPort connectivity. Sapphire equips this mid-range gaming graphics card with an effective dual-slot cooler that keeps the graphics card running well at a low temperature while not being noisy.