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PSU Overloading question

post #1 of 3
Thread Starter 
Is there a good way to know when you're overtaxing your PSU?

For whatever reasons, let's not get into why, I am running 4 Radeon HD5870s full steam ahead right now on a single machine. It is running off a Seasonic X750 power supply.

I plugged this system into my kill-a-watts monitor along with my room lamp, DSL modem, wireless router, and laptop computer. Before turning on the system the kill-a-watts measured about 61Watts of power draw.

After turning on the system and firing up all the cards the kill-a-watts is measuring 955-969Watts from the wall. Assuming that I can subtract 61 watts for the other components, that's 900Watts from the wall. Assuming again gold standard 87% efficiency that's .87*900 = 783Watts.

Killawatts can be +- a few % innaccurate so on top of already going slightly over spec I can potentially be going a few percent more over spec. So I'm not totally comfortable with this, but I don't really want to go buy another power supply. Are there any signs I should watch out for while I leave this running to see if it is doomed to death or not?

The X750 is quite hot, although for whatever reason the fan seems to be barely spinning (I can barely feel any air coming out the back). I don't take that to be a great sign thusfar. Anything else I should be checking?
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CPUMotherboardGraphicsRAM
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Bleeding Edge
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CPUMotherboardGraphicsRAM
i7 2600k @ 5.0Ghz 24/7 ASUS P8P67PRO AMD 5870x2 8GB GSkill Ripjaw X 1600 @ CL8 
Hard DriveOSMonitorKeyboard
ADATA S599 64GB SSD + 2x 1TB Spinpoint (Raid 0) Windows 7 64Bit Dell 23" Razer Lycosa 
PowerCase
Seasonic X650 HAF X 
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post #2 of 3
Quote:
Originally Posted by ocpokey View Post
Is there a good way to know when you're overtaxing your PSU?

For whatever reasons, let's not get into why, I am running 4 Radeon HD5870s full steam ahead right now on a single machine. It is running off a Seasonic X750 power supply.

I plugged this system into my kill-a-watts monitor along with my room lamp, DSL modem, wireless router, and laptop computer. Before turning on the system the kill-a-watts measured about 61Watts of power draw.

After turning on the system and firing up all the cards the kill-a-watts is measuring 955-969Watts from the wall. Assuming that I can subtract 61 watts for the other components, that's 900Watts from the wall. Assuming again gold standard 87% efficiency that's .87*900 = 783Watts.

Killawatts can be +- a few % innaccurate so on top of already going slightly over spec I can potentially be going a few percent more over spec. So I'm not totally comfortable with this, but I don't really want to go buy another power supply. Are there any signs I should watch out for while I leave this running to see if it is doomed to death or not?

The X750 is quite hot, although for whatever reason the fan seems to be barely spinning (I can barely feel any air coming out the back). I don't take that to be a great sign thusfar. Anything else I should be checking?

With 4 5870's you are 100% overloading thats not very safe at all, and i don't think there are many signs just maybe one day it will fry.... It will get stressed, a good 850w should do it
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Blue Box
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500 gb seagate Sony Corsair H60 Windows 7 Ultimate 64bit 
MonitorKeyboardPowerCase
22 inch V7 1680x1050 Steelseries Shift Keyboard Antec Neo eco 620w Cm 690 w/ 5 140mm fans 
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post #3 of 3
Thread Starter 
100% overloading would mean that I was doubling the capacity of the PSU which clearly I'm not. My meters estimates put it at 4% over rated wattage, which shouldn't be too bad really.

BUT I'm a big fat wuss honestly, and I baby my hardware way way way more than I should, so I actually have picked up a hale90 850W to run the 4 5870s, which should only be loaded to about 90-95% of its capacity and thus be no cause for concern. Makes me sad that my x750 never really got to see much action, such a sweet supply.

I hope I didn't make a mistake in not cheaping out and getting a tx850, they're only $110 right now. I liked the gold rated efficiency, and 6xPCI-E though.
Bleeding Edge
(13 items)
 
  
CPUMotherboardGraphicsRAM
i7 2600k @ 5.0Ghz 24/7 ASUS P8P67PRO AMD 5870x2 8GB GSkill Ripjaw X 1600 @ CL8 
Hard DriveOSMonitorKeyboard
ADATA S599 64GB SSD + 2x 1TB Spinpoint (Raid 0) Windows 7 64Bit Dell 23" Razer Lycosa 
PowerCase
Seasonic X650 HAF X 
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Bleeding Edge
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CPUMotherboardGraphicsRAM
i7 2600k @ 5.0Ghz 24/7 ASUS P8P67PRO AMD 5870x2 8GB GSkill Ripjaw X 1600 @ CL8 
Hard DriveOSMonitorKeyboard
ADATA S599 64GB SSD + 2x 1TB Spinpoint (Raid 0) Windows 7 64Bit Dell 23" Razer Lycosa 
PowerCase
Seasonic X650 HAF X 
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