450 WATTS??? I just noticed this. Are they serious? How can they have 12 cores and dual GPU running on 450Watts?!
That's got to be a typo.
They seem to be serious. If go to design overview page the Mac Pro puts out 12db worth of noise at idle. That only cranks up to around 18db a load. (perhaps not max load) One way to assist in that is to put a hard cap on the power (as opposed to magical fan properties. It is probably good; not magical. )
Also look at what they are doing with A7 system designs.
http://www.anandtech.com/show/7460/apple-ipad-air-review/3
"Full Blast" for all of 100 seconds is actually long enough for a couple ( if not most ) of the 'drag racing' benchmarks that more than a few folks get their underwear in a twist about. Incrementally move the tests from one major computational package to another and it will turn in good numbers.
Coupled with OS X 10.9's "race to sleep" and they also may be able to do "blast, recover, repeat" cycles on a wide variety of workloads that will deliver acceptable user action/response. Non human driven workloads are the only loads that typical drive the engine throttle to 100% power and keep it there for extended periods of time.
There is also slop/safety factor in TDP specs also. If Fred, Barney , Wilma , and Betty all design different components with different coolers there is typically a small factor built in to account from the possibly conflicting designs. If Apple carefully measured and removed the margins they could punt on power/disposal that never gets generated/needed.
Doubtful all of these brings things all the way back to even, but it probably isn't quite as ridiculous as it looks. However, high enough that 6, let alone 7, TFLOPs is going to largely be a mirage on anything be the most contrived codebase+dataset.
. If that 450Watt number is accurate, they're seriously down-clocking these things.
Or not running them all at the same time. The common trait where all the CPU and GPU packages are going is that they don't run at a single speed. It is all about dynamic range. The computer should down clock when there is nothing to do.
A little Extra math: Each TB port is 10 watts - add 60 watts, each USB 3.0 port is 4.5 watts - add 18 watts.
The TDP 'clawbacks' mentioned above might give these sorts of of numbers depending upon how generous the margins are. But yes, back when folks were saying that 400W power supply was going to help deliver far lower pricing I did the similar math.
Those can get chucked by just using powered externals if going to load up on internal consumption (e.g., a 100% dedicated compute node could be spared being a peripheral power distribution center. )