Power Requirements for graphics card

magicianz

Hi guys!

I'm looking at graphics cards for a new build and the power requirements are constantly confusing me. Taking this card for an example on Dabs.iehttp://www.dabs.ie/products/sapphire-technology-amd-radeon-r9-290-4gb-pci-express-3-0-hdmi-90MV.html?refs=55570000-498470000&src=3.

Under Specifications > System Requirements, it says it requires 750W. Now surely thats not the power draw of the card and cooling system as that is a massive draw. I know NVIDIA usually require lower power consumption but 750W is massive! Or is this just a minimum recommended power supply for everything in the system? If so, how do they make these figures up?

Cheers!

Luck100

750 W is the recommended wattage rating for your pc's PSU. They usually set a really inflated recommended number to cover their a*s for cases where people have really junky PSUs which can't come close to their rated value without blowing up.

The actual power draw is 'total dissipated power' (TDP), just google for that if you don't see it. For the R9 290 it's 275 watts.
http://www.techpowerup.com/gpudb/2397/radeon-r9-290.html

So you should budget for 275 watts for the GPU alone, plus some margin for overclocking/surges.

Luck100

For example, if you have the R9 290 (275 watts TDP) and i5 4570 (84 watts) you should budget:

275 (GPU) + 84 (CPU) + 30 (drives, etc) = 389 watts nominal TDP.

To have some room for overclocking and avoid running your PSU at 100% all the time, I would look for a 500 PSU in the example above. More if you want to do heavy overclocking or the PSU is a brand with lesser reputation. Also think about if you want the possibility of crossfire (second GPU) down the road, then you'd probably want 800-850 watts minimum.

Gumbi

Luck100 wrote: »

For example, if you have the R9 290 (275 watts TDP) and i5 4570 (84 watts) you should budget:

275 (GPU) + 84 (CPU) + 30 (drives, etc) = 389 watts nominal TDP.

To have some room for overclocking and avoid running your PSU at 100% all the time, I would look for a 500 PSU in the example above. More if you want to do heavy overclocking or the PSU is a brand with lesser reputation. Also think about if you want the possibility of crossfire (second GPU) down the road, then you'd probably want 800-850 watts minimum.

Not to mention the AC --> DC conversion where 10 - 20% of power is lost.

Luck100

Gumbi wrote: »

Not to mention the AC --> DC conversion where 10 - 20% of power is lost.

PSUs are rated on the maximum DC power supplied to your system, not the power drawn from the wall.

Gumbi

Luck100 wrote: »

PSUs are rated on the maximum DC power supplied to your system, not the power drawn from the wall.

Yeah that's true, just wanted to throw it in... that being said it is superfluous :P

Luck100

Gumbi wrote: »

Yeah that's true, just wanted to throw it in... that being said it is superfluous :P

No worries...just didn't want OP to think he needs another 10-20% in the power budget for conversion loss.

magicianz

Thanks guys! In my case so, FX-8350 (TDP: 125W), Sapphire R9 290 tri-x(TDP: 275W), water cooler, drives, etc., I'm looking at around 450W or so being used, throw on another 100-150W for overclocking everything, 700W - 750W should do me?

Luck100

Yeah, 700-750 watts from any of the decent manufacturers should definitely have you covered.

SterlingArcher

Try the be quiet 700w silver.

Or a similar corsair.

yawhat!

600 watt would be fine

http://www.hardwareversand.de/500+-+600+Watts/74421/Corsair+CX+Series+Modular+CX600M%2C+600W.article

magicianz

SterlingArcher wrote: »

Try the be quiet 700w silver.

Or a similar corsair.

Are be quiet! a respected brand now? Only heard of them recently! I was looking at this 850W RM Series Corsair for my supply at the moment, for future possible expansions!

SterlingArcher

magicianz wrote: »

Are be quiet! a respected brand now? Only heard of them recently! I was looking at this 850W RM Series Corsair for my supply at the moment, for future possible expansions!

Yeah they make pretty good PSU. Name sounds gimmicky, but is actually true to the product.

That 850w going to run you a few quid.
but if you're not on a budget. Go ahead.