Always great to hear about parallelization becoming more widely adopted. The only thing that I don't get is the part about the GPU - it takes a lot of computation to tie up an 8800GT for a full minute. Also, it shouldn't take the 1-3 seconds he described to send a 45 sec .wav file over a PCI Express 2.0 x16 bus (~3-4 GB/s bandwidth IIRC).

I'm not sure what's causing those runtimes, but the fact that it spread over 8 cores that well suggests that it almost qualifies as embarrassingly parallel, which a GPU really should be great for. This makes me really wonder about the maturity of Apple's / nVidia's OpenCL implementation.

EDIT: I just ran a few of the OpenCL SDK demos and can confirm that it is 1-2 orders of magnitude slower than the same demo running in CUDA. The bandwidth for copying memory to / from the device should still be high, though.

My OpenCL Bandwidth Test results: ~/NVIDIA_GPU_Computing_SDK/OpenCL/bin/linux/release$ ./oclBandwidthTest

./oclBandwidthTest Starting...

Running on...

Device GeForce 8400M GT

Quick Mode

Host to Device Bandwidth, 1 Device(s), Paged memory, direct access

   Transfer Size (Bytes)	Bandwidth(MB/s)

   33554432			1600.9

Device to Host Bandwidth, 1 Device(s), Paged memory, direct access Transfer Size (Bytes) Bandwidth(MB/s)

   33554432			1235.1

Device to Device Bandwidth, 1 Device(s) Transfer Size (Bytes) Bandwidth(MB/s)

   33554432			6069.7

TEST PASSED

Press <Enter> to Quit...