450W PSU for 500W GPU

[babadoctor]

I wanted to use my R9 270x 4GB with a computer that has a PSU rated for 450W.

The box says that the minimal requirement is 500W for the GPU. Can I still run it on 450W, or will the computer not work?

[Mooshi]

Majority of single GPU builds with a high end card use <400w when pushed to the limits. No way a R9 270X is pushing 500w. The "minimum" manufacturer recommended wattage tends to be hilariously exaggerated to cover themselves in case someone decided to use the cheapest, oldest PSU from a prebuilt with <70% efficiency. 

 

I've ran more demanding systems with a 430w unit without issue. 

[OsuMasterz]

What are the other specs from the PC?

I also doubt that the 270x uses that much power because I've ran that card on a CX450m before...

[Godlygamer23]

The title is a bit misleading(or maybe it has to deal with lack of knowledge). The wattage recommendation is not because the video card pulls 500W. It's an estimation used in relation to the rest of the components where the video card might pull 150ish watts on average, or at most. 

[babadoctor]

3 minutes ago, Godlygamer23 said:

The title is a bit misleading(or maybe it has to deal with lack of knowledge). The wattage recommendation is not because the video card pulls 500W. It's an estimation used in relation to the rest of the components where the video card might pull 150ish watts on average, or at most. 

That's good to know. 

 

3 minutes ago, Mooshi said:

Majority of single GPU builds with a high end card use <400w when pushed to the limits. No way a R9 270X is pushing 500w. The "minimum" manufacturer recommended wattage tends to be hilariously exaggerated to cover themselves in case someone decided to use the cheapest, oldest PSU from a prebuilt with <70% efficiency. 

 

I've ran more demanding systems with a 430w unit without issue. 

I see. Thanks for clearing that up!

[TheKDub]

11 minutes ago, babadoctor said:

I wanted to use my R9 270x 4GB with a computer that has a PSU rated for 450W.

The box says that the minimal requirement is 500W for the GPU. Can I still run it on 450W, or will the computer not work?

Depending on the efficiency of the power supply, you should be alright, though I'd recommend upgrading the power supply when you can.

[ARikozuM]

5 minutes ago, TheKDub said:

Depending on the efficiency of the power supply, you should be alright, though I'd recommend upgrading the power supply when you can.

Efficiency only has to do with the power pulled from the wall. A quality PSU will offer all its advertised watts, i.e. 500W, but a 80% efficiency means the PSU is pulling 625W from the wall.

 

@babadoctor What PSU do you have? Can you check how many amps your PSU will provide form the 12V rail?

[babadoctor]

55 minutes ago, ARikozuM said:

Efficiency only has to do with the power pulled from the wall. A quality PSU will offer all its advertised watts, i.e. 500W, but a 80% efficiency means the PSU is pulling 625W from the wall.

 

@babadoctor What PSU do you have? Can you check how many amps your PSU will provide form the 12V rail?

The PSU seems to be a 450W Antec

Not sure the specifics, but it's a generic one.

[ARikozuM]

6 minutes ago, babadoctor said:

The PSU seems to be a 450W Antec

Not sure the specifics, but it's a generic one.

Just look on the PSU itself for a sticker showing voltage and rails. Search for the 12V and see if it supplies the full wattage from that rail.

 

Usually looks like this:

Spoiler

Courtesy of Newegg.com: Rosewill Quark 750W.

See how the +12V rail supplies 744W? You want your PSU to supply at least 300W (to be safe). If it doesn't supply that much, I would consider a PSU upgrade in the future.

[STRMfrmXMN]

The "500W" recommendation is just your video card manufacturer trying to cover their ass so a shitty PSU doesn't set fire to your GPU or break it through ridiculous ripple. A CX430 could power a 270X without issue. 

[babadoctor]

6 hours ago, ARikozuM said:

Just look on the PSU itself for a sticker showing voltage and rails. Search for the 12V and see if it supplies the full wattage from that rail.

 

Usually looks like this:

  Hide contents

Courtesy of Newegg.com: Rosewill Quark 750W.

See how the +12V rail supplies 744W? You want your PSU to supply at least 300W (to be safe). If it doesn't supply that much, I would consider a PSU upgrade in the future.

Alright. Thank you for telling me about that.