I work in a startup security firm, and I need to build a GPU-based to brute force password/hashes, which can be used to validate password strength and test hashing algorithms. I expect some high processing demand, so it needs to be a high spec.
What (detailed) configuration do you recommend?
Would it be better to invest in a massive 1k+ cores CUDA/OpenCL GPU or to build a cluster of less-costly cards? Is "mining hardware" like these a good option?
Update due to answers: Due to customer requirements I can't outsource this to EC2 or similar cloud solutions.