What happens when power supply is not powerful enough?

16 replies [Last post]
Minde47
Offline
Joined: 03/07/2012
Posts: 36

Hi,
Some people say that if your PSU is not powerful enough the pc will turn it self off, and some people say that some components will burn. So wich is it? I'm planing to upgrade video card to 7970, but I have only 500W PSU.
Thanks.

spawnkiller
spawnkiller's picture
Offline
Joined: 05/06/2012
Posts: 310

Anything could happen from running Correctly for a certain time then the PC no longer boots, random BSOD, Crash/Freezes, Burning Components, PC wont turn on, Internal PSU faillure (smoke or blown fuse, i've seen both) and any thing that you can imagine... A good 500w like a Seasonic one (i have an Antec NeoHE 500w that have Seasonic internals) would easily run that (i had run 2X560ti + a Q6600 overclocked for years now) but this PSU was rated 500w continous output @50 clesius so it's 650-700w in reality so it really depend on the brand, the model and the price paid, a 80-100$ 500w is a lot more reliable than a 50$ 500w PSU...

What's the brand and the model of your PSU ???

If it's a cheap one, I'd strongly suggest that you invest on a better PSU (600w from a good brand like Antec, Corsair, Seasonic, Enermax, CoolerMaster are some suggestions) and buy a 7950 instead to not raise the budget too much as PSU is a costly components when you want a decent one... (i also recommend a 80+ Bronze at minimum and Gold or Platinum if possible with your budget...)

Gaming PC: MSI Z77A-G45 ::: Intel Core I7 3770k @ 4.83Ghz ::: EVGA GTX680SC Signature ~1300mhz Boost/7122mhz ram ::: 16GB 4*4gb G.Skill 2240mhz CL10 ::: ASUS Xonar DX ::: Crucial M4 128gb (windows) + Intel 330 180gb (Steam games) + 1TB Caviar Black (storage) ::: Cooler Master Silent Pro Gold M1000 ::: Antec P280 ::: Noctua NHU12P SE2 ::: ASUS VE247H ::: Logitech G510 ::: Cooler Master Storm Sentinel II ::: Logitech X530 ::: Steelseries Siberia V-2 Black & gold edition

98% Of people under 25 surround their minds with rap music, if you're part of the 2% that stayed with rock, put this in your signature, ROCK IS BETTER!

Razear
Razear's picture
Offline
Joined: 12/30/2008
Posts: 1105

Best case scenario if the PSU wattage is insufficient is that the PSU will shut itself down to protect itself. Worst case scenario would be damage to other components and/or the PSU itself. Normally an overloaded PSU will cause a lot of system instability.

To answer your question about the 7970, a 500W PSU should be fine for that card. This follows the assumption that you are using a quality PSU and not simply a generic one.

Mordeux
Mordeux's picture
Offline
Joined: 04/19/2004
Posts: 93

500 watts will work for now. If you ever hit peak wattage, you will probably end up somewhere close to 400 watts. You should still consider a stronger Power Supply. In general, a PSU should run underneath 60% of its capacity. When it operates over this limit, it suffers in efficiency and the overall system is stressed to its limits which will decrease a PSU's lifespan as well as possible instability (this usually isn't a problem with quality PSUs). You should also check on your PSUs actual wattage verses its rated wattage.

X-Mas 2012 (most of it):
Coolermaster CM Storm || SeaSonic SS-660XP || ASUS P8Z77-V PREMIUM || Intel Core i7-3770K || 16 Gigabytes Corsair-Veng. || eVGA GTX 560ti || Audigy 2 ZS Platinum || 240GB Intel 520/ 2TB Samsung HDD || Liteon Blu-ray || Logitech G700 || Microsoft SIDEWINDER X4 || 20.1" NEC WMGX^2 || Onkyo TX-SR702 Receiver (with Bowers & Wilkins Speakers) || Sennheiser HD600 Headphones

Tivon
Tivon's picture
Offline
Joined: 04/26/2002
Posts: 1834

I wouldn't worry about burning fires inside your computer, generally it would just shut off during random gaming events or not post at all.

A single Radeon HD 7970 graphics card from AMD specifies a minimum of a 500 Watt or greater power supply.

Generally these requirements are loosely based on a wide assumption that your power supply is somewhat good and that you only have the standard number of components installed. More specifically the 500watts requirement is about having enough Amps to power the video card and other devices.

The 7970 will claim about 25A (25-Amps) for itself. Check the specifications of your Power Supply to see if you can supply 25A. If your system meets those requirements and it doesn't lock up during heavy usage then you should be fine, but I'd recommended a PSU upgrade in the future.

Don't test my skills, I was trained by myself! Check out my Gaming Videos!

Minde47
Offline
Joined: 03/07/2012
Posts: 36

Yeah I got the cheap one, CHIEFTEC 500W 80+ bronze. From what I read I see better not to risk. Thank you all.

Mordeux
Mordeux's picture
Offline
Joined: 04/19/2004
Posts: 93

It isn't necessarily bad. If Delta made that particular Chieftec PSU, then it is probably top notch.

Minde47
Offline
Joined: 03/07/2012
Posts: 36

Nah it's just cheap one I paid ~130LT/2.4= ~54 USD. And what about 7950 would 500W be enough? I have AMD Phenom II 1055T not overclocked for more info. And card that I think of buying is club 3d royalking, so it's overclocked and still has headroom for more.
And this is what it says at shop where I bought the PSU:
PS2 Form factor / 500 Watts Intel P4 / AMD Athlon XP / ATX 12V 2.3 Specification / 230V input / 120mm fan / active PFC (Power Factor Correction) / AFC (Automatic Fanspeed Control) / OVP (Over Voltage Protection) / SCP (Short Circuit Protection) / OCP (Over Current Protection) / MTBF: >100.000 h / 80% Efficiency only 230V

Mordeux
Mordeux's picture
Offline
Joined: 04/19/2004
Posts: 93

Personally, I think you'll be fine.

Minde47
Offline
Joined: 03/07/2012
Posts: 36

I'll give it a try then, thank you.

Tivon
Tivon's picture
Offline
Joined: 04/26/2002
Posts: 1834

Yeah, just give it a try first. I did a search and could find a wide range of specs for that PSU and they mostly hinted at two 12v rails with 20A, so that would combine for 40a. This also reads as two 12v rails (20amps x 12volts) = 240watts, Then multiply that PSU rail by two and you really have a total of 480watts.

Courage
Courage's picture
Offline
Joined: 01/28/2012
Posts: 14

I had Q9300 and GTX275OC, but only 550w Power supply, I knew it was lack of power because the fan of my CPU was increasing speed automatically to full speed, the components were overheating especially the graphic card. After a year it died. (working with high temperatures for long time). After that I bought 1000w power supply and all went back to normal.

Antec 1200 ; OCZ 1000w PSU ; Intel i7 3770K ; Antec Kuhler H2O 920 ; ASUS Sabertooth Z77 ; ASUS GTX660 2Gb ; G.Skill Ripjaws 4x8Gb ; OCZ Vertex 4 SSD 2x256Gb RAID 0 ; Samsung 2x1Tb RAID 0 ; LG W2486 24" ; Razer Lycosa Mirror ; Razer Carcharias ; Roccat Kone+ ; Roccat Alumic

TheRealMan
TheRealMan's picture
Offline
Joined: 05/25/2007
Posts: 46

Not to sound cruel to any one person but this is a very bad idea and i don't think he should try it! No name PSUs usually don't have overload protection, PFC, quality caps, true wattage ratting, or high efficiency, and more! If you push a crap power supply even close to its rated limits, you risk damage. Without the safeguards like overload protection, PFC, ect, you risk horrible things like power spikes discharging into all the components, Poorly filtered DC current, which would result in damage. That's just off the top of my head. Your computer is not worth risking over the replacement cost of the PSU. EVEN if it does work, its pushed to its limit 24/7 it will fail sooner then later.

Sorry, just being devils advocate!

-TRM

GIGABYTE-X38-DS4 water cooled chipset - GTX 460 - Seagate 32MB(c) 500GB + Intel 120Gb SSD -- C2Q Q6600 3.4Ghz-8GB(4X2GB)- Thermaltake Toughpower 700W - Win 7 64-Bit Ultimate - CM-690
--Laptop T5850 C2D-750GB Seagate Momentous XT - 6GB 1X4/1X2 DDR2
--Server C2Q 6600@2.4- 4GB 2x2 - ATi 4850 Upgraded cooler - Seasonic 500 Modular - 2X 1.5TB WD/green 1X 320WD 1X2TB WD/black

Courage
Courage's picture
Offline
Joined: 01/28/2012
Posts: 14

If it's not a good brand power supply it will not supply the power written on it..
Don't forget the efficiency of power supplies!
Look at Efficiency level certifications first

nellis51
Offline
Joined: 10/09/2012
Posts: 10

Buy a name brand, quality power supply with at least a 3 year warranty.

Dan0myte
Dan0myte's picture
Offline
Joined: 10/25/2001
Posts: 316

Components burning? That's absurd.

If anything, you may overheat your PSU if you're overloading it which will severely reduce it's lifespan. As it's been mentioned before, watch for computer crashes while you're working or playing games. Without enough amperage, or if the voltage drops below it's threshold, the motherboard won't function and processing will stop.

Dan's Server Rack:
Norco RPC-470 -> E8500 @ 3.85GHz, GA-EP45-UD3P, 4Gb OCZ 1066 DDR2, OCZ Vertex 60Gb SSD, Seagate 7200.11 320Gb, Zalman 600W Heatpipe PSU, Vista x64 Pro
Norco RPC-270 -> AMD64 3200+, ASRock K8Upgrade-VM800, 1Gb DDR400, WD 80Gb (O/S), WD 1TB Green (Media), parallel 1000Mbs network cards, WinXP Pro

PcTestCard.co.uk
PcTestCard.co.uk's picture
Offline
Joined: 10/20/2012
Posts: 12

If the PSU is not able to supply the necessary power ratings, the computer may auto reboot when certain app launches and need the peak power consumption that exceed the PSU ratings.

Of course, under power will cause the unstable elecricity current running among the components on the mobo and shortened the life span of the parts.

Hope this helps.
Bill
Tech Manager, WPTinc.

Hope this helps.

Bill
Tech Manager - WPTinc.