AMD Radeon R9 285 Review: Tonga GPU Makes its Debut
 

As a mid-range GPU, the R9 285 is meant to deliver mainstream performance at a competitive price. The "Tonga" GPU is essentially a newer, cheaper to produce version of the tried and true "Tahiti" GPU, with features such as DirectX 12 support and next-gen CrossFire. It does have an inferior memory controller, however.

http://www.techspot.com/review/873-amd-radeon-r9-285/