If it reaches 100% and no key is found I will be laughing my head off for two reasons:
1) Hahaha, all those review sites recommending to use RC5 as a good overclock test tool without giving a real thought to system integrity - ooohhhhh it can crunch number when overclocked by 150MHz so it must be stable and accurate........ yeah, just keep believing that, I'm sure the force is strong with you.
2) It will have done a great deal to prove that 64-bit encryption is safe from a distributed brute force attack (which is the complete opposite to what the original intention was) until quantum computers become mainstream in..... ooohhh say 100 years........