Power issues with GTX 750 Ti

[cyberdunks]

Purchased a EVGA GTX 750 Ti a few days ago. Installed it. Its very unstable and I think it might be power supply problem. After doing some digging around I've found out that it requires 20 amps, but my power supply is only a 17 amp on a 12 volt rail. The power supply itself measures at 480watts and has 2x 12 volt rails.

Will buying a +12v 20amp power supply fix this problem? I'm guess so.

My other question is, is the 6pin video card connector from the power supply going to be what I use, or will I need to use one that connects from another cable from the power supply such as the molex connectors?

 

[Thelps]

From what I have gathered at the EVGA website, the Geforce GTX 750 Ti does not require a PSU power connector - it draws all required power from the PCIe x16 slot on the motherboard.

The instability of the GPU is almost certainly linked to low amp supply via the PSU's +12v rail, yes.

Keep in mind - when purchasing a new PSU get one that is slightly overpowered for your system. This will help give you some breathing room when it comes to upgrades you may consider in future.

Also, consider a modular PSU. This will allow you to swap in only the cables you need, leaving more space in the case and providing further adaptability should you consider GPU upgrades as time goes on.

 

[cyberdunks]

So, since it draws all the power from the PCIe x16 slot, does the motherboard have to allow that much amperage or is that covered as part of the PCIe x16 spec?

I'd hate to plug in the new power supply and toast a working board due to over amping.

When it comes to hardware, I'm usually pretty good at this stuff, however when it comes to power, watts, amps, volts, ohms.. I get lost.

 

[RobCrezz]

You cannot "over amp" it.

It just sounds like your "480w" psu is junk.

Can you elaborate on how you think it is "unstable" ?

 

[cyberdunks]

It runs for about 20 minutes when in use by demanding games it hard freezes the system. After doing some math I've figured out that the power supply is inadequate. I'm trying to pull 500watts worth of hardware off of it, time to make a trip to the NewEgg or Microcenter. Thank you so much for the replys/responses.

 

[RobCrezz]

It runs for about 20 minutes when in use by demanding games it hard freezes the system. After doing some math I've figured out that the power supply is inadequate. I'm trying to pull 500watts worth of hardware off of it, time to make a trip to the NewEgg or Microcenter. Thank you so much for the replys/responses.

Its highly unlikely you are pulling 500w, but I suspect your "480w" psu cannot deliver what it should.

 

[omega215d]

The +12v line is supplying juice to more than just the GPU so it's best that you get a PSU that can supply more than 40amp just to be safe and future proof it a bit. Just be sure to check max load on the rail(s) as well. IIRC 2 molex plugs are required for one 6pin PCI-E adapter. So when shopping for a new PSU find one that comes with PCI-E plugs (which is a given nowadays from the well known brands). You can also return that 750 Ti for one that's more like the reference design that doesn't utilize a PCI-E plug along with a new PSU.

 

[jundel1954]

So, since it draws all the power from the PCIe x16 slot, does the motherboard have to allow that much amperage or is that covered as part of the PCIe x16 spec?

I'd hate to plug in the new power supply and toast a working board due to over amping.

When it comes to hardware, I'm usually pretty good at this stuff, however when it comes to power, watts, amps, volts, ohms.. I get lost.

 

[jundel1954]

Sir, first lets go to power supplies; in honestly given rated power as labelled... it should be the sum up of all the outputs, eg 12v with a rating of 20 amps, 5v ...20amps, 3.3... 20amps, the total power should be 406 watts. And they could label that as a 450 watts since there are safety factors included in the design. Your Video card, the manufacturer's rating is 60 watts ... thats the total consumption of your video card ...if in case we'll only consider the 12volts then it draws 5 amps only. So the best thing you can do is to know your mother board's consumption first then the add on accessories like you dvd cd rom reader and copier and then add your video card's power. Note, in buying power supply focus on the 12v and 5v ampere ratings... the higher the better. maintain at least a 20% higher rating. So there you have already a guide as to what power supply you would need in your computer.