Announced over the summer when AMD was celebrating their 30 years of graphics celebration was the Radeon R9 285, a $250 graphics card built on the company's latest GCN graphics processor technology to replace the Radeon R9 280. We finally have our hands on a Radeon R9 285 "Tonga" for delivering the first look at its Linux performance.
The Radeon R9 285 offers roughly the same performance as the Radeon R9 280 while at the same price. However, for the Radeon R9 285 comes a new GPU compared to the R9 280 being derived from the three-year-old Tahiti GPU. The Radeon R9 285 is powered by AMD's Tonga GPU and is the first GPU on the market using the GCN 1.2 architecture revision. The GCN 1.2 "Volcanic Islands" revision features better performance improvements (particularly for tessellation), a new video encoder/decoder, and an updated ISA that's more efficient.
The AMD Radeon R9 285 graphics card features a 918MHz Boost core clock, 5.5GHz GDDR5 video memory clock with a 256-bit memory bus, and the reference design utilizes 2GB of video memory. The R9 285 Tonga GPU has 1792 Stream processors, 112 texture units, and 32 ROPs. Like the other Radeon Rx 200 series hardware, the R9 285 is still manufactured on a TSMC 28nm processor.
Since September when the Radeon R9 285 began to ship was an updated Catalyst Linux driver with support for Tonga. When it comes to the AMD open-source support, however, there is none right now. The Radeon R9 285 isn't going to be supported by the current-generation Radeon stack but rather is going to be the first GPU on the new AMDGPU Linux graphics stack. That code will start rolling out in the weeks/months ahead so for now Linux users are limited to just using the Catalyst binary blob.
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