PSU 12v Rail?

[xnocturnal]

Hey i recently setup a new gaming system and i am monitoring my psu rails and my 12v rail seems to be running at 11.6-11.7 v sometimes less when in game. Could this be a sign of not enough power on my 12v rails? new psu?

Thanks

Noc

 

[blazorthon]

The voltage is rarely exactly what it is supposed to be. You should be fine with that PSU, unless it has other problems.

 

[xnocturnal]

Well, under load it falls to 11.5/11.6 I assume that's normal

 

[blazorthon]

It's normal for the voltages of the rails to vary and sometimes, they can vary pretty far from their rated voltage. That shouldn't cause any problems.

 

[DJDeCiBeL]

TOO low is under 11.4V as that's out of tolerance for the ATX 2.x specification, but software monitoring is always a bit inaccurate.

 

[Rugger]

The PSU should shut down if it actually goes out of spec.

 

[rinval]

i use an older system this a highend thermaltake PSU and get around the same and have not had any trouble until the rails started dropping below 11.3-4. that is when i would start seeing artifacts and the fans speed up and slow down slightly. so in my opinion the closer the 12 u can get the better but your voltages seem to be in the operable range. if you have a decent brand power supply like a corsair or seasonic i wouldn't fret to much as they have good consistent voltages. if ur running a cheap off brand power supply you might want to look at upgrading to a better brand in the near future. keep in mind that when your buying a PSU shoot for a wattage 30+% higher than you system requires. doing this a buying a good brand should stop this from happening in the future.

newegg has a decent tool for showing what psu you will need but id still shoot for at least 20-30% higher for good measure.

http://images10.newegg.com/BizIntell/tool/psucalc/index.html?name=Power-Supply-Wattage-Calculator

 

[JackNaylorPE]

Well, under load it falls to 11.5/11.6 I assume that's normal

The ATX standard allows for a 5% voltage variation to meet "spec" .... you're at 4.2% with 11.5 which to my mind is rather HUGE. Your OC's are to a large part determined by voltage stability and 0.5 volt drop is, to my mind, far from stable. I look for units that can maintain no more than 1% voltage variation.

Here for example you'll see some of the units I use frequently which maintains no more than 1% voltage variation (0.5 in the 2nd case) above / blow 12.00 volts

http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story2&reid=142
http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story2&reid=101

 

[Rugger]

newegg has a decent tool for showing what psu you will need but id still shoot for at least 20-30% higher for good measure.

http://images10.newegg.com/BizIntell/tool/psucalc/index.html?name=Power-Supply-Wattage-Calculator

There's no need to put a 20-30% buffer zone into all the online calculator recommendations. They already put a buffer in there....GPU mfrs put a buffer in there, CPU mfrs put some buffer in there, all the mfrs put some buffer in their recommendations. Modern PCs consume significantly less power than most people think. A recent article on power consumption in three modern PCs: http://www.silentpcreview.com/article1245-page1.html
Notice that a PC with an i5 2500K and an HD 6870 at full load running Prime95 and Furmark only consumed 237W!

 

[delluser1]

^+1

OP, buy a new power supply

 

[Rugger]

I'm pretty sure that the recommendation from Dell is because of the low voltage of your 12V rail. What is the make/model of your PSU?

Edit: Changed instability to read low voltage on the 12V rail.

 

[delluser1]

^ Yep, a .4v drop is more than I want to see, especially when it starts .3 below 12v

 

[xnocturnal]

So. Who is correct here? ...I've got a bunch of mixed answers

 

[DJDeCiBeL]

So. Who is correct here? ...I've got a bunch of mixed answers

Your PSU is on the edge of causing instability, but what is the brand and model of your PSU?

 

[xnocturnal]

Cool master 500watt Extreme Plus. Was pretty cheap.

 

[rinval]

There's no need to put a 20-30% buffer zone into all the online calculator recommendations. They already put a buffer in there....GPU mfrs put a buffer in there, CPU mfrs put some buffer in there, all the mfrs put some buffer in their recommendations. Modern PCs consume significantly less power than most people think. A recent article on power consumption in three modern PCs: http://www.silentpcreview.com/article1245-page1.html
Notice that a PC with an i5 2500K and an HD 6870 at full load running Prime95 and Furmark only consumed 237W!

I agree that newegg gives a good ideal of exactly what you need to your specific build with exactly what you have in it and at the exact clocks your set to + about 20ish% overhead. but you need to keep in mind that unless you go with a HIGH end good name PSU with 80% bronze or better your PSU wattage can dip as high as 30+% from what the label states.. and the hotter it gets the more wattage you loose that is y i always throw the extra 20% over what newegg shows which gives me a good 40ish% cushion in case i upgrade or the psu overheats and drops wattage production. it also gives me a little room for overclocking without any major impact on the system.

anyway back on topic if your voltage stays consistent where its at you might be ok but its ify. if its bouncing then you will want to upgrade PSUs to a higher wattage or better brand depending. keep in mind if your overclocking you want as stable voltage on your rails as possible as well as keeping it as close to 12 volt mark as possible to keep from running to issues. bouncing voltage on your rails = harder work for your VRM to maintain the proper voltage to your cpu. the more the CPU voltage bounces the more instability or performance degradation you will see.

 

[DJDeCiBeL]

Cool master 500watt Extreme Plus. Was pretty cheap.

Yep, there's your problem. It's new PSU time for you, I believe.

 

[xnocturnal]

Awesome. Okay thanks

 

[xnocturnal]

Best answer selected by xnocturnal.

 

[xnocturnal]

went with a 750watt ThermalTake TR2 RV, 80+ bronze. Thoughts?

 

[blazorthon]

Not the brand that I'd go with, but it should at least be an improvement.

 

[xnocturnal]

Yeah its modular which is nice and I figured 80+ bronze was a steal with 750watts for 79.99

 

[blazorthon]

Keep in mind that a lot of power supplies that seem cheap for their features are that cheap because that's all that they're worth. It's an improvement, but ThermalTake isn't nearly the best out there.

 

[xnocturnal]

Yes I'm sure ii can dish out another hundred dollars if it decides to take a turn

 

[Agiel]

my games some time crash and sometime pc shut off, i see bellow 11.3v under load, no OC here all is stock, my CX600M is dying i guess, should i get the EVGA 600B ?? ppol say its better more stable and has higher end Caps ??