How much high can the 12V rail be with no harm ?

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RicoBOT

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Hi again guys. I ve had a lot of trouble with shut downs last days and it seems like my OCZ 850 W is not providing well , since i got a 500W old one and the system is working fine again. But i got worried about the voltages and was Reading a little about it. Someone said that 3.3 V should be 3.3 V and no more So my question : s this AIDA64 readings ok , or should i go out and buy a new one :
3.3 --- 3.683
5 --- 5.040
12 --- 12.414
GPUcore - 1.063
CPUcore - 1.068

My specs :
Gigabyte Z77M-D3H (ashamed)
Ivy Core 3770k
2X 8 GB Kingston 1333
HD5870 2 GB Vapor X
PCIE ASUS Xonar
SSD 240 + Hitachi 7200 4 TB + SANSUNG 7200 1.5 TB
BR drive

thanks for the help.
 
Solution
das_stig
Power Supply Voltage Tolerances (ATX v2.2)

Voltage Rail Tolerance Minimum Voltage Maximum Voltage
+3.3VDC ± 5% +3.135 VDC +3.465 VDC
+5VDC ± 5% +4.750 VDC +5.250 VDC
+5VSB ± 5% +4.750 VDC +5.250 VDC
-5VDC (if used) ± 10% -4.500 VDC -5.500 VDC
+12VDC ± 5% +11.400 VDC +12.600 VDC
-12VDC ± 10% -10.800 VDC - 13.200 VDC
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md1032

md1032

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Your 12 V rail may be fine. Some power supplies run a little high by default to keep the voltage from dipping too low under load. I have personally seen a few perfectly functioning power supplies with that kind of idle voltage. The thing that matters is how those voltages look under "full load".

To test a power supply under full load, I run SpeedFan and plot all of the voltages on the real-time graph. Then I simultaneously run Intel Burn Test and Furmark to put the CPU and GPU both at 100% load (or close to it). Wait at least 10 seconds for the voltages to stabilize at their lower values, and then turn off the stress tests. Examine all three rails for their lowest point relative to the idle point, but especially the 12 V rail. Any deviation more than 10% from the idle value is an indication that something is seriously wrong, and for you, since you're running such a high wattage supply relative to your load, you should see no more than 2.5% deviation IMO.

At one point I had a cheap 680 W power supply that would idle at 12.2 V and would "spike" as low as 10.4 V, which is about -15% relative to idle. This computer would randomly restart at times...a classic power supply problem symptom. Well, that power supply failed within a couple weeks of me "noting" that problem.

The 3.3 V rail is a bit off if that is indeed the true value, but it's probably within the ability of the motherboard to regulate. I would recommend purchasing a quality multimeter and measuring it yourself if you are really worried.

http://www.informit.com/articles/article.aspx?p=31105&seqNum=12
 
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das_stig

das_stig

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Jul 24, 2009
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Power Supply Voltage Tolerances (ATX v2.2)

Voltage Rail Tolerance Minimum Voltage Maximum Voltage
+3.3VDC ± 5% +3.135 VDC +3.465 VDC
+5VDC ± 5% +4.750 VDC +5.250 VDC
+5VSB ± 5% +4.750 VDC +5.250 VDC
-5VDC (if used) ± 10% -4.500 VDC -5.500 VDC
+12VDC ± 5% +11.400 VDC +12.600 VDC
-12VDC ± 10% -10.800 VDC - 13.200 VDC
 
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RicoBOT

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Hi again. Im doing some testing now. Running furmark Furmark at full HD, Prime95 multi core and AIDA64 for monitoring voltage.
3.3 -> max 3,683 -> min 3,663
5 -> max 5,04 -> min 5,01
12 -> max 12,491 -> min 12,260

it seems pretty stable to me.
 
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RicoBOT

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great than. I might hold up with this one for a while. Just one last thing, ive been checking other posts, but in your opnion , can a high consuming system reduce the VGA performance if the PSU is not giving enough juice. I mean, if the 3770k drains up too much, i would experience slow frame rates or it would just shut down
 
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RicoBOT

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Great. I thought the same. Just to add on that matter, what happened is that i was thinking i had a deffective VGA, than ive gonne out and bought a HD7970 3 GB and brought it home, but told the guys on the shop that i would like to return it on the other morning if it was not the problem. Than as i connected it the system booted just fine (it was restarting in the posting process all the time with the 5870 - thats why i thought it was VGA problem). As it worked , i realized i was right. I got into Windows 8 desktop and started checking things, all going fine, than i tried to run Project Reality. It went ok , util the game itself was loading to start the 3D game (after the menu and all that), than it shut down suddnely again and restarted. I had the same thing when running All Saints, GTA IV and Metro 2033 ( The menus were loading ok, but when going inside the 3d it restarted). Than i figured out it was probably energy shortage when the new 7970 board was sucking for power for the 3d. Thats what gave me the ideia of trying the 500 W old PSU.
Than again i think you´re right , it probably just hangs or reset the PC.
thanks again
 
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