Bitcoin Forum
January 22, 2017, 10:27:44 PM *
News: Latest stable version of Bitcoin Core: 0.13.2  [Torrent]. (New!)
 
   Home   Help Search Donate Login Register  
Pages: [1]
  Print  
Author Topic: 3x6990 system powers off with 6 GPUs active  (Read 1448 times)
Tril
Full Member
***
Offline Offline

Activity: 212


View Profile
July 14, 2011, 06:06:10 PM
 #1

I can run 5 GPUs all day long, but if I try mining on 6 GPUs, the system turns off in half an hour. The power LED blinks and case fans keep spinning, and I need to flip the power switch off and back on to get it to boot.  According to multiple places AX1200 and 890FXA-GD70 can handle 3x6990.  The GPU temperatures are always very good (under 85C). I have underclocked video RAM to 350MHz. The machine has a Sempron 145 CPU and one IDE hard drive. USB instead of IDE doesn't help. Do I need a PCI-E extender or is there an easier solution?
Advertised sites are not endorsed by the Bitcoin Forum. They may be unsafe, untrustworthy, or illegal in your jurisdiction. Advertise here.
Tril
Full Member
***
Offline Offline

Activity: 212


View Profile
July 14, 2011, 06:57:31 PM
 #2

I just changed the OC switches on all 3 cards from "2" to "1" and it turned off even faster.
stellan0r
Hero Member
*****
Offline Offline

Activity: 490


Medical Translations for Bitcoins


View Profile
July 14, 2011, 07:49:12 PM
 #3

In my opinion 1200W is not enough for your purpose. probably the PSU gets too hot because it's running at maximum load, don't forget that 1200W with 90% efficiency results in 1080W real usable power. even if 1 6990 with 2 GPUs uses only 346W, you would reach 1038W with 6 GPUs not even counting in the mainboard and cpu (appox. 80W) + cooling you have and hdd (1100W+)
5 GPUs result in round about 1000W overall use, which seems to be the limit for your PSU with 24/7 usage.

so, either get a 1250W enermax revolution85+ or something bigger or keep it running with 5 gpus.


edit: turning the switches from 2 to 1 (into OC mode?) drains even more power(~210W per GPU), which results in faster shutdown of the psu to prevent your personal computer-meltdown ;-)

Allgemeine Gesundheitsberatung gegen Bitcoin-Zahlung. Bei Fragen einfach eine PM schicken!
If you want to send a thank you: BTC "1PZJvKvarRviQRQWejpvXW2j4e1xbT8MZb" / Doge "DHtN2YEFg1obv2VFps8RwQSL6xL1RRYyXN"
Tril
Full Member
***
Offline Offline

Activity: 212


View Profile
July 14, 2011, 09:34:54 PM
 #4

If 1200W is not enough, how come these guys sell a 3x6990 rig with 1200W:

http://www.bitcoinrigs.com/products/Professional-Rig-2000.html

and why does this page have a pre-built 3x6990 system with 1200w:

https://en.bitcoin.it/wiki/Mining_rig#Three_ATI_6990s,_Approximately_2.1_Ghash/s

and why does this guy say it works too?

https://forum.bitcoin.org/index.php?topic=27963.0
grue
Global Moderator
Legendary
*
Offline Offline

Activity: 1932



View Profile
July 14, 2011, 10:58:21 PM
 #5

some brands may perform better than others.

It is pitch black. You are likely to be eaten by a grue.

Tired of annoying signature ads? Ad block for signatures
WebMonkey
Member
**
Offline Offline

Activity: 100



View Profile WWW
July 15, 2011, 12:12:25 AM
 #6

the last link says the guy took off the side panel and directed a box fan at it.
you now, a 120v fan probably 12 or 14 inches.

cooling the cards down will effectively reduce the load on the power supply.

which allows the supply to "handle" the 3 cards.

just one possible solution/scenario.

the answer to the original question is most certainly insufficient power availability.

good luck!

'monkey

Team Calvary Racing

support the ministry
BTC: 1KXvwsDwRM2RUdwtnff3feuYrHH2a1JHnR
LTC: LWdf2pnmQqBkg7GP7rmfGYCZaAQrjsu2Yx
Tril
Full Member
***
Offline Offline

Activity: 212


View Profile
July 15, 2011, 04:58:19 AM
 #7

I disconnected the 3 HAF-X case fans, and the system has remained stable with all 6 GPUs running for close to an hour so far.  Both sides of the case are off, with no external fans needed yet (it's pretty cool today).
stellan0r
Hero Member
*****
Offline Offline

Activity: 490


Medical Translations for Bitcoins


View Profile
July 15, 2011, 05:34:38 AM
 #8

if it's working with everyone else, you probably got a "monday PSU" Wink )

but it's the power, you proved it with the fans (also I would not recommend to disconnect cooling parts Smiley )

Allgemeine Gesundheitsberatung gegen Bitcoin-Zahlung. Bei Fragen einfach eine PM schicken!
If you want to send a thank you: BTC "1PZJvKvarRviQRQWejpvXW2j4e1xbT8MZb" / Doge "DHtN2YEFg1obv2VFps8RwQSL6xL1RRYyXN"
Xephan
Jr. Member
*
Offline Offline

Activity: 42


View Profile
July 15, 2011, 08:09:34 PM
 #9

I can run 5 GPUs all day long, but if I try mining on 6 GPUs, the system turns off in half an hour. The power LED blinks and case fans keep spinning, and I need to flip the power switch off and back on to get it to boot.  According to multiple places AX1200 and 890FXA-GD70 can handle 3x6990.  The GPU temperatures are always very good (under 85C). I have underclocked video RAM to 350MHz. The machine has a Sempron 145 CPU and one IDE hard drive. USB instead of IDE doesn't help. Do I need a PCI-E extender or is there an easier solution?


Based on available data, a single 6990 draw close to 400W, mainly on the +12V at full load. With 3 cards, you're looking at 1200W which is the rated limit for the AX-1200. Add in the power required by the motherboard, CPU and such, not much compared to the GPU but as you discovered, just enough to tip the over-current protection. Downclocking the ram chips don't really help much as they generally consume about 1~2 watts per chip, halving that makes very little difference.

It's usually not a good idea to push a PSU at close to 100% for extended period of time, dies faster and therefore reduce your real income from mining. Getting a "cheap" auxilliary 450W PSU just to connect a couple of those +12V connectors may be a better long term solution.

186q9YUW3x8TVHC5aYBEqgZZYMxft8Cw9f
Xephan
Jr. Member
*
Offline Offline

Activity: 42


View Profile
July 15, 2011, 08:13:27 PM
 #10

In my opinion 1200W is not enough for your purpose. probably the PSU gets too hot because it's running at maximum load, don't forget that 1200W with 90% efficiency results in 1080W real usable power.

Hope you won't mind me correcting you on this. A 1200W PSU with 90% efficiency will (or should) provide 1200W of real usable power. It just takes about close to 1400W of AC power to provide that 1200W. So the difference between a 85% efficient 1200W PSU and a 90% efficient 1200W is really in the cost of running the same load, but they will both be able to (assuming real 1200W capable PSU) drive a 1200W load.

186q9YUW3x8TVHC5aYBEqgZZYMxft8Cw9f
stellan0r
Hero Member
*****
Offline Offline

Activity: 490


Medical Translations for Bitcoins


View Profile
July 15, 2011, 08:42:49 PM
 #11

In my opinion 1200W is not enough for your purpose. probably the PSU gets too hot because it's running at maximum load, don't forget that 1200W with 90% efficiency results in 1080W real usable power.

Hope you won't mind me correcting you on this. A 1200W PSU with 90% efficiency will (or should) provide 1200W of real usable power. It just takes about close to 1400W of AC power to provide that 1200W. So the difference between a 85% efficient 1200W PSU and a 90% efficient 1200W is really in the cost of running the same load, but they will both be able to (assuming real 1200W capable PSU) drive a 1200W load.


Sure not, thanks for that info! Was never sure if it means 1200w = 90% or 1200w = 100% Smiley

Allgemeine Gesundheitsberatung gegen Bitcoin-Zahlung. Bei Fragen einfach eine PM schicken!
If you want to send a thank you: BTC "1PZJvKvarRviQRQWejpvXW2j4e1xbT8MZb" / Doge "DHtN2YEFg1obv2VFps8RwQSL6xL1RRYyXN"
grue
Global Moderator
Legendary
*
Offline Offline

Activity: 1932



View Profile
July 15, 2011, 09:34:39 PM
 #12

In my opinion 1200W is not enough for your purpose. probably the PSU gets too hot because it's running at maximum load, don't forget that 1200W with 90% efficiency results in 1080W real usable power.

Hope you won't mind me correcting you on this. A 1200W PSU with 90% efficiency will (or should) provide 1200W of real usable power. It just takes about close to 1400W of AC power to provide that 1200W. So the difference between a 85% efficient 1200W PSU and a 90% efficient 1200W is really in the cost of running the same load, but they will both be able to (assuming real 1200W capable PSU) drive a 1200W load.

nah, it's better marketing to say its power consumption, rather than its power output.

It is pitch black. You are likely to be eaten by a grue.

Tired of annoying signature ads? Ad block for signatures
Pages: [1]
  Print  
 
Jump to:  

Sponsored by , a Bitcoin-accepting VPN.
Powered by MySQL Powered by PHP Powered by SMF 1.1.19 | SMF © 2006-2009, Simple Machines Valid XHTML 1.0! Valid CSS!