Quote Originally Posted by Pantsu View Post
Afaik Evergreen was never starved for shaders. 5870 and 5850 have basically the same perf clock-to-clock. 5830 sucked because it had only 16 ROPs, so it barely beat a 5770 with 40% more shaders. It was easy for Barts to increase the efficiency by increasing the ROP count compared to the amount of shaders. It's basically an OC'd 5830 with double the ROPs. That's the secret to Barts increased perf per mm^2. Now with Cayman the same doesn't apply, so it's up to the shader architecture changes to give similar increases in performance.
Funny thing is that you can't put Barts efficiency gains on increase in ROP. here is what AT said in its review:

it’s worth noting that internally AMD was throwing around 2 designs for Barts: a 16 SIMD (1280 SP) 16 ROP design, and a 14 SIMD (1120 SP) 32 ROP design that they ultimately went with. The 14/32 design was faster, but only by 2%. This along with the ease of porting the design from Cypress made it the right choice for AMD, but it also means that Cypress/Barts is not exclusively bound on the shader/texture side or the ROP/raster side.
http://www.anandtech.com/show/3987/a...range-market/2