What happens when your SLI setup pulls more power than the PSU can provide?

I would ask:

What happens when your SLI setup pulls more power than the PSU can provide?

Would the system just shut down? Would you have to turn the switch off and on manually on the PSU to get it to respond?

Also, what happens when your system overheats? Would the system also just flat out shut down?

Thank you for helping

A bad or poor power supply can cause numerous problems for a PC. A bad power supply can cause lockups, reboots, and generate excessive heat, not to mention shortening the life span of other components. An under powered power supply can also limit system expansion.

Provide more specifics on your setup, so opinions can be given.


Last year I had a problem with my CPU over heating the PC would just shut down it was a AMD anthlon x2

If you want you can run a bench mark tool like vantage and monitor the voltage with a volt meter and measure the 12V at a molex connector (yellow to black).

[QUOTE=SubZero;2497616]I would ask:

What happens when your SLI setup pulls more power than the PSU can provide? Thank you for helping[/QUOTE] Usually the nVidia internal systems shut down all kind of processes, making your video setup very very slow. Better invest in a good and stable PSU.

Thank you for replies

I have more information:

Nvidia GTX 295 is recommended at 680 watt Power Supply and a 700 watt was purchased to be used with the card.

Failure of system would be like tripping of a breaker where it would all shut down the complete PC and require manual switch off and then on of the power switch on the Power Supply.

It seems diagnosed that the system request more power than is possible by the Power Supply. But not in Watts. Instead:

“The existing 700 watt Power Supply did not provide enough Amps on the 12 volt rails to support the GTX 295”

700 watt has 21 Amps on Rail 1 and 22 Amps on Rail 2 but with maximum draw at 38 Amps total.

It is recommended that there be at least 46 Amps available on 12 volt rails, in addition to what is required by the rest of the system for proper operation. 46 Amps dedicated to the GTX 295 that is.

Thank you for helping

Just to clarify, Watts = Power

Amps are also directly related to power.

38 Amps total for a 700W PSU is rather low, it can be 60+ on a good PSU. For example SeaSonic X750 Gold

Thank you for reply

Here is model to replace it with:


Antec TruePower New TP-750 Blue 750W Continuous Power ATX12V V2.3 / EPS12V V2.91 SLI Certified CrossFire Ready 80 PLUS BRONZE Certified Active PFC “compatible with Core i7/Core i5” Power Supply - Retail

4 of 12 volt rails with each of 4 having 25 Amps

2 of those 25 Amps rail are for the video card and 50 dedicated Amps should show proper support of power.

Well, if it were me :smiley: I would do a little cut and splice action. All it would require is a 5" wire to go from one of the cables containing molex connectors and tap into the yellow wire and solder it and tape it with electrical tape, then bring the other end to the pciex16 cable and solder the other end to the yellow in that cable. I would do it a second time with another cable from another yellow wire run, and bridge that to the other pciex16 cable feeding the video card. Its really not hard and can be done without cutting any of the wires on the psu, you would just strip back some of the insulation, an auto stripping tool would spread the insulation nicely. Of course this would void your warranty.

edit: I use a stripper like this one, ebay link

Thank you for reply

For Antec it says:

12 volt rail 1 = (20 + 4) Motherboard
12 volt rail 1 = Molex Cable from PSU
12 volt rail 1 = SATA Cable from PSU

12 volt rail 2 = 4 pin ATX12V
12 volt rail 2 = 8 pin EPS12V

12 volt rail 3 = PCI-E w/ Blue Stripe (6 + 2 plug capable)

12 volt rail 4 = PCI-E w/ Green Stripe (6 + 2 plug capable)

GTX 295 = 8 plug and 6 plug
GTX 285 = 6 plug and 6 plug

Rail 3 and 4 are for video card only

I am not familiar enough with electronic to cut wires to make it work. If I had knowledge I would wish to convert my Logitech Wireless Trackball into a Wired Trackball to avoid signal interference. I would welcome help on that project.

My idea would simply divert some power from rail 1, to either rail 3 or 4. Your other option would be to sell that PSU and get one that is more Gamer friendly (rail wise).

Thank you for reply

Antec TruePower New TP-750 Blue seem to be game friendly and is only cost at $120 USD. I think good value, so I will try it. I will post follow-up.

50 Amps dedicated to video card that asks 46 Amps on the system. Sounds to be impressive.

I’m no rocket scientist, but I play an electrician at work. 50 Amps @ 12 Volts = 600 Watts! That’s only 150 Watts for the rest of the system.
:cool:}Ohm’s Law…It’s a Law we all can live with{:cool:

The 25 amp per rail rating is just a maximum per rail, not a total 12V amperage rating. The total current for that PSU is 62A at 12V and thats a ‘max’ rating, so it can’t do that continuously (744W), and it rates the 5V and the 3.3V combined as 170W (max). Heavily biased to the 12V power thats for sure.

My comment before about spicing the wires was based on the thought that the TP-750 PSU wasn’t cutting it, but then I realized thats the new one that you don’t have yet, so thats my mistake. So disregard that statement. :slight_smile:

The TP-750 looks like a good deal, good luck with it.

Tnx Eric. I guess the silicon parts really don’t suck that much power…

Thank you for commenting in reply

The Antec 750 has fixed everything compared to the other PSU. No shut-down at any time since replacement of original 700. 38a on 12v was old 700, 50a on 12v is new 750 and GTX-295 has now become very stable and no amount of testing on the new 750 Antec can cause shutdown. All run perfect as far as I can tell when testing for day after day.

Thank you for helping and thank Antec for solid PSU at decent price.