GPUs are definitely dead for bitcoin. You'll get something like 10^9th more efficient SHA256 hashing from an ASIC than a GPU. But for many other coins, there a

GPUs are definitely dead for bitcoin. You'll get something like 10^9th more efficient SHA256 hashing from an ASIC than a GPU. But for many other coins, there are two big factors bringing GPUs back into the game for mining: - Lots of alt-coins competing for popularity; many might have ASIC mining implementations in the future, but there either hasn't been enough time or enough money to be made by doing it yet. - There's been various research done to reduce the potential gain in efficiency from an ASIC implementation over using commodity hardware. This was done in response to the concentrating effect of ASIC mining operations, which put a greater percentage of global hashpower in a smaller set of hands. The main way ethereum implements this "ASIC resistance" is by exercising memory bandwidth -- an area where GPUs are already quite optimized -- in the hashing algorithm. https://github.com/ethereum/wiki/wiki/Ethash https://github.com/ethereum/wiki/wiki/Ethash goes into detail.