[Bf-committers] Possible hope for AMD Radeon cards and Cycles GPU rendering

[Akira Shirakawa]

Hello,

On BlenderArtists.org we managed through some dirty "hacking" (not 
really source code hacking, but you get the idea) to make supported AMD 
Radeon cards to GPU render with Cycles on Blender 2.63 at extremely good 
speeds.

Speaking of the probably famous BMW1M-MikePan test scene, we got actual 
render times of:

Radeon HD7770: 0:55
Radeon HD6850: 1:40

Some issue still persist. Mainly, by using a 2.62 compiled OpenCL kernel 
we restricted ourselves to Cycles features implemented up to Blender 
version 2.62. Also for some reason it appears that the OpenCL kernel 
gets compiled every time a render is started, which adds significantly 
to the overall render time. Lastly, so far only 12.5 beta AMD Catalyst 
drivers for Windows appear to make the magic work.

However, we're nothing more than end-users who don't really understand 
what's going on. Just that these preliminary results seem *very* 
promising and demonstrate that recent AMD video cards can be really good 
for rendering.

It would be nice if developers gave a detailed look at this so that the 
real causes could be investigated and proper fixes, implemented:

http://blenderartists.org/forum/showthread.php?254521-A-good-news-for-AMD-ATI-Graphic-cards-owners/page4

(also see the rest of this thread for more information and background)

Cheers,
S.A.