[Xcelerate]

It wouldn't be as much as you'd think. For one thing, Titan uses ECC nVidia GPUs, which (if I remember correctly), are NOT optimal for producing bitcoin; AMD GPUs are better. I know you mentioned not paying for electricity, but the power bill for Titan would far exceed any bitcoin produced.

[hn-miw-i]

Efficency is mostly about the cost of the hardware (purchase and running costs), power usage and performance. Purchase, running cost and power usage are not part of your efficiency calculation.

ATI cards have traditionally had better hashing (in general, rainbow table gen, jtr, BTC) because they have a larger number of Execution Units per core, however clocked slower, than the nvidia. Higher number of EU allows better exploitation of parallelism important for the performance of hashing.

This is the fastest damn computer, its not a brand loyalty GM vs Ford, Coke vs Pepsi, Android vs iOS duality. Oh it's got nvidia, not optimized for hashing. It's going to kick the arse of any consumer or professional grade GPU on the market...

[maaku]

No, the point was integer-ops vs floating-point. AMD kills NVIDIA on integer-op performance, which SHA256 uses.