The inevitable rise of GPUs and more specialized hardware was being discussed by Satoshi and others on bitcointalk around early 2010. Just my memory as a source

The inevitable rise of GPUs and more specialized hardware was being discussed by Satoshi and others on bitcointalk around early 2010. Just my memory as a source, or you can see some discussion of emails between Laszlo Hanecz who bought the 19K BTC pizza and was GPU mining and Satoshi.