In June/08 I talked to Joost Batenburg, one of the researchers
who uses the FASTRA system (at the time they were looking
into better cooling solutions and I had some suggestions).
The important point about this system is that it does not
involve any communication between the GPUs, ie. SLI is
irrelevant. Indeed, the gaming 3DMark06 score for the system
is not that high, partly because it's only really using one
card for the test (the mbd is a Crossfire board, chosen for
other reasons).
Indeed, after it was first announced, some people asked why
they didn't use 9800GTX cards instead of 9800GX2s. The GTX
is faster for games, but not by much, whereas the tomography
computations the researchers are doing can fully use both
GPUs on a GX2 card, giving a virtually perfect linear scaling
for multiple GPUs, ie. much better than a GTX card.
Oddly enough, there *is* a commercial system that can use
up to 8 gfx cards (ie. 16 GPUs), namely SGI's top-end VS
system (up 8 quad-core Opterons, 8 x PCIe cards, 256GB RAM),
which is a rebadged version of the top-end system from BOXX.
However, FASTRA is cheaper, and they don't need much in the
way of main-CPU power anyway so a system supporting lots of
normal CPUs would be a waste.
FASTRA is interesting because of how it is used, but a bit
strange that toms would put it into the list since it's not
a games machine.
Btw, the researchers' previous 'device', as toms puts it,
was a cluster of 256 dual-core Opterons.
For full details of FASTRA, see:
http/fastra.ua.ac.be/en/faq.html
http/fastra.ua.ac.be/en/technicalfaq.html
Supporting lots of gfx 'pipes' is nothing new though; SGI's
been doing it for nearly 20 years.
Ian.
SGI Guru.
mapesdhs@yahoo.com