There has been some confusion and resentment expressed about the arrival of GPU miners for MemoryCoin. How could GPU miners be here so quickly when MemoryCoin was supposed to be GPU-resistant?
GPUs
GPU means ‘Graphics Processing Unit’, but it is more accurate nowadays to think of them as ‘General Processing Units’, made up, as they are, of multiple under-powered processors. They can do nearly any paralellizable task faster than a CPU but are much more difficult to program for.
Two Approaches
One way to approach the problem is to have a very complex algorithm – this is the protection afforded by Quark and PrimeCoin. The proof-of-work is so complicated that it takes a long time to develop code that will run well on GPUs. When the code is developed, it represents a big investment and so is unlikely to be released. You won’t even hear about it while it is profitable to its creators. When GPU miners are eventually released, they will blow CPU miners out of the water. This approach is a short-term one.
The Long Term Approach
MemoryCoin aims to keep CPU miners in the game long-term. This requires a different approach that plays to the strengths of CPUs and capitalizes on the weaknesses of GPUs. MemoryCoin’s algorithm does this by maximizing main memory use and using the AES-NI set that modern CPUs have. However, even with these measures, GPUs can still beat CPUs. The algorithm is simple and so GPU miners have appeared publicly and rapidly.
The Upsides
The upside is that the GPUs are limited in their advantage over CPUs. They are between 2 or 3 times faster per dollar. Compare that to 100X for Bitcoin or 10X for Litecoin. This means CPUs will continue to be viable and we’re unlikely to see GPU farms built for, nor directed, at MemoryCoin. Commercial miners won’t be able to compete with the zero-capital costs of widespread individual mining. Individuals will still be able to convert electricity to MemoryCoin at a reasonable rate.
The other upside is that GPU miners are a now known quantity and there is a level playing field. With other coins, it can be uncertain as to whether GPU miners exist, how much faster they are, and who has access to them.