Russia rules

russian-flag-bike21

Few months back I started to collect most powerful folders configuration data and set up quite popular  “Most Powerful Folders” thread in Folding@Home Forum.

Now Russian folders occupied #1 positions in both in GPU and SMP/CPU folding category:

GPU: 70 629 PPD Xmemory + Total OverClock Core i7 940 + 4 x NVIDIA GTX295

SMP: 15 059 PPD Lendy Q9300@3.63 2x2Gb DDR2-969, WinXP SP3

Good luck to them in powerfolding!

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2 000 000 points folding milestone

 

Folding@Home 2M certificate

Folding@Home 2M certificate

32 GPU folding rig cooling diagram

so, whole system is air-cooled. I didn’t use liquid cooling because of 3 main reasons (1) cost; (2) added risk of something going wrong; (3) complexity of montage in rack system.

As You see, cold air is pushed into 19″ closed rack cabinet. GPU-s suck cold air from the back part of the cabinet and pull it out from the front. I have 3 x 170 mm 240V AC fans doung the job in 4U cooling panel. More pictures after the break…

Dual PSU PC system

 

8 GPU node with 4 x GTX295 double-gpu cards powered by dual Chieftec 850W PSUs

8 GPU node with 4 x GTX295 double-gpu cards powered by dual Chieftec 850W PSU's

 

 

So, why 2 PSU’s instead of 1 powerful?

Say, that we have to drive 4 x GeForce GTX295 cards ‘a  max 289 Watts. It’s combined load is  1360 W, including rest of the system (CPU, chipset, HDD, etc…). So, minimum requirement is 1400W PSU. But this is bad idea — PSU’s are efficient in 40-75% load range, in that range they meet 80Plus and other promises. At 90-100% load they get un-efficient, dissipate extra heat and get loud, fans are running at max speed. So, at 1360 W load we need 1800 W PSU to run it in sweet-spot. Here we have few serious issues: (1) they are not widely sold; (2) they are not cost efficient, cost per watt gets very high, eg 2 x 750 W PSU-s sell 50% less than 1 x 1500; (3) PSU’s with 4 pairs of 6-pin anf 8-pin PCI-E connectors are rare.

And how to run them synchroneusly 

One solution is to make cable. In that case You dont need to modify PSU cables and all remains original:

Dual PSU solution, master PSU, slave PSU remains original

Dual PSU solution, master PSU, slave PSU remains original

Second solution is to modify ONE psu cable to control other:

Using one of these solutions Master PSU controls Slave PSU, switches it on and off.

In my case I run:

Master PSU

  • System board
  • HDD
  • 2 x GTX 295

Slave PSU

  • 2 x GTX 295

Both PSU-s run cool and quiet and I can sleep well, knowing that I don’t push my system to limit.