Windows: 1052 CPUs per teraflop
Linux: 821.5 CPUs per teraflop
Mac: 1762 CPUs per teraflop
I.e., it takes twice as many Macs as it does Linux machines to produce the same amount of work. Not that this really means much - it probably reflects how well optimized each client is, rather than real raw performance.
I believe we've done the same math only using inverse divisions. Linux computers do twice as much useful work as do Apples. Linix is stwice as good as Apple.