[Beowulf] GPU Beowulf Clusters

[Gerry Creager]

Mark Hahn wrote:
>>> Be very very sure that consumer geforces can go in 1u boxes. It's not 
>>> so much
>>> the space as much as I'm skeptical with their ability of handling the 
>>> thermal
>>> issues. They are just not designed for this kind of work.
>>
>> I've had to go to 2u and eventually to larger boxes because of power 
>> supply and air-flow requirements. This is a big issue.
> 
> I'm a bit puzzled here.  sumermicro sells servers that take either two 
> M1060's, or two C1060's, or two of any pcie 2 x16 cpus.  their airflow 
> design seems at least thought-about, and their PSU is 1400W.
> 
> C1060 specs merely say "200W max, 160W typical" - which is probably 
> about the same as gtx275 according to wikipedia.  so something like 600W 
> expected from 1U - not really that hard, especially if you don't
> have a wall of 40u racks full of them...

A little over a year ago, a 1u 600w supply was a bit difficult to find 
for < $400, and additional fans for one required buying a specialty 1u 
case. I could have driven node price over $4k with CPUs, memory, a large 
onboard scratch, etc. I, too, was building a proof-of-concept box at the 
time. Now, it's used almost daily by several folks, and I'm thinking of 
building a new POC to house 4x gx's...

And still no user interest in CUDA, and I don't have enough time to play 
without user interest, with my own research program that isn't 
computational science.

>>> Note that geforces are overclocked (my gtx 285 by 30% compared to a 
>>> tesla with
>>> the same chip)
> 
> well, they're tuned differently: gf cards have substantially higher memory
> clocks and lower shader clocks.  tesla has higher shader and substantially
> slower memory clocks (presumably because there are more loads on the bus.)

Didn't realize. Thanks.

>>> and are actively cooled, which means that you need to get air
>>> flowing into the side fan. That's exactly why they put the tesla m 
>>> and not the
>>> c into those boxes.
> 
> why is this a problem with 1U?  or do you really mean "double-wide cards
> don't provide enough clearance in 1U to get air to the card's intake"?

That's what *I* found, anyway.  Yeah, what you said.  Sorry, I thought 
that was obvious. When you turn one of those cards on its side, you do 
have trouble with card-width clearance.

gerry