Comment by microarchitect | Hacker News Reader

Comment by microarchitect | Hacker News Reader

Calling this a "supercomputer" is a bit disingenuous. The most powerful supercomputer today can do 10.5 Petaflops on the Linpack benchmark [1]. The 500th most powerful supercomputer can do 51 Teraflops.

If the authors actually tried to measure Linpack scores on their cluster, they'd find that peak performance would be much worse than the 12 teraflops they're claiming as "peak" performance. This link [2] seems to indicate that one S2050 along with a fairly fast CPU gives you about 0.7 teraflops. Even if they get perfect scaling across GPUs, which they won't, and if they could solve all the heating issues with their design, they won't get more than about 0.7*6.5 = 4.55 TFLOPS peak on linpack.

In any case, many (39 out of 500 to be precise) of the most powerful supercomputers in the world also use GPUs to accelerate certain applications so there's simply no way this thing would be faster than those computers.

[1] http://www.top500.org/lists/2011/11/press-release [2] http://hpl-calculator.sourceforge.net/Howto-HPL-GPU.pdf

One S2050 has four M2050s, not two (I inferred this assumption from your 6.5 multiple).

I'd like more information on the CPUs and CPU/GPU bus of this FASTRA II. CPUs are really gaining back a lot of their performance relative to GPUs - an M2090 is only about 5-10x faster than the newer Intel Xeons in a properly multithreaded program that pays attention to the NUMA nodes. This is efficient enough that for large simulations which do not fit on one GPU, running portions of the simulation on CPU easily overcomes the CPU/GPU communication overhead in terms of performance.

>I'd like more information on the CPUs and CPU/GPU bus of this FASTRA II.

"the graphics cards, which are connected to the motherboard by flexible riser cables." - so this sounds like typical PCIe based design. Usually the bundle of GPU cards on PCIe backplane is placed into separate case which connected back to the CPU host, and in this case they engineered it into one big case thus each card getting it's own x16/x8 pipe.

In general such "supercomputer" is cheaper, hardware-wise, than equivalent CPU-based, yet it is still more expensive human labor (ie. programming) -wise.

cough 12 terraflops, not petra

Oh right. Thanks for catching that typo.

Agreed, thank you. "Supercomputer" is a continually moving goal-post that basically means "more computing power than you can achieve with personal computers." Supercomputers push the limits of the performance that we can achieve. If you can fit it inside of a PC case, then you're not pushing the limits of the kind of performance we can achieve.

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