I don't know if it has anything to do with GPUs, I had thought it was due to memory, as referenced on the wiki page for Litecoin: "Litecoin uses scrypt in its p

I don't know if it has anything to do with GPUs, I had thought it was due to memory, as referenced on the wiki page for Litecoin: "Litecoin uses scrypt in its proof-of-work algorithm, a sequential memory-hard function requiring asymptotically more memory than an algorithm which is not memory-hard."