Quote from: omri on September 17, 2011, 09:09:34 AM

Quote from: CoinHunter on September 17, 2011, 07:40:53 AM

Quite well since that's up there with the fastest. I haven't quite benchmarked the new algorithm extensively (because it's not completely optimized yet) but it's about 1000 times more intensive than the last method on CPU. And the changes should make GPUs not a viable option for some time. It's utilizing SHA256 and one of the new SHA-3 candidates "BLAKE" along with some other features which the CPU is better at handling than GPU.

I've had a look at "BLAKE" and it seams o be using similar basic operation to the current SHA-256. How is it less efficient at GPU mining then the current SHA2/256 algorithm? It does not include the non-linear elements Maj and Ch from SHA2, but these were not the main selling points of the GPUs anyway.
I am not a GPU expert, so there is probably something major that I missed here, can somebody please explain it.

It's not just a straight hashing. There are pre and post processing of hashes using certain techniques which favor CPU over GPU. They have to be executed in order and are very hard to split up into smaller problems.

Of course this won't stop the ability for it to run on multiple GPU "threads" per se, but there are other techniques in there which don't favor current GPU technology. Comparatively more memory is used and in ways which aren't conducive to the best memory reading/writing of GPUs.

All this being said I'm not going to guarantee CPU will always be faster, perhaps there are some OpenCL coders who can make some magic happen. I am not an OpenCL guru as I haven't had much experience with it to this point in time.... so we will have to wait and see how long CPU will be faster as there's no other way to know. I can also improve it going forward without needing to restart the chain so if anyone can offer suggestions after source is released they are welcome to.