On Mon, Aug 22, 2016 at 5:36 PM, Mark Hahn <h...@mcmaster.ca> wrote: >> Extra, the direct contact cooling stuff must still have the fans in the >> nodes to keep the dimms/disks/power supplies cool... thus use considerably >> more power than nodes without fans. > > > why do you say "considerably"? 1u muffin fans are annoying and not that > efficient, but even 1U could still use blowers. and it's not as if > you need a lot of airflow to keep 5-20W of support hardware cool. > (that would be for non-extreme numbers of disks/dimms/nics - though it > occurs to me that motherboards also have some power regulation in them, > and if 2 sockets are drawing 250w, then 90% efficient regulation would still > mean 28W extra heat to dissipate.) > > iirc a typical 1U fan dissipates up to ~3W, but that's only when running > full on (screaming 14krpm...). not to mention the wide availability of > simple 4-system-in-2u chassis (more efficient fans).
i don't have any empirical evidence only 2nd hand information from when i was an employee at Appro. We did some serious system power tuning for some large customers who had very stringent power requirements. but in any case i think your power numbers are on the low side for auxiliary power draw in a system. _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
