Building a PC, Thoughts about this Specs

[vivster]

sc94597 said:

vivster said:

sc94597 said:

vivster said:

re more than enough to have the system running at full power. You can take 550W to be on the safe side but more will be thrown out money and your PSU will run less efficent at idle performance.

Normally this is true, but the R9 280/280x/290 are very power-hungry. They can get as high as 280 Watts consumption. If his CPU wasn't also power-hungry he could likely get by with 500W, but his CPU has benchmarked to max at about 160W. That can be up to 420-440W usage for the CPU+ GPU alone. Considering that many of the average 500W rated PSU's really run around 450W, I wouldn't risk it. Heck, I have a Pentium G3258 (max watt consumption about 70 w) and an 280x, and was a bit worried that my 500W PSU wasn't enough. There are some good deals on 550W-600W PSU's though. I bought my 500W PSU for $40 and got a $20 rebate, which went to my Pokemon Alpha Sapphire purchase. The 600W version was only $15 more. 

Well I checked my sources before saying this. A whole system with overclocked 280X and a 4770k consumes about 350W. The 8350 consumes about 100W more than the i7. That's why 500W would be fine(if it is a good PSU it will deliver close to 500W) and 550W to be safe. Everything above that would be wasted unless he plans to overclock his CPU and get an overclocked 290X. I'm not used calculating with AMD.

My next system will be with an i7 and big Maxwell and I'm planning on getting a PSU around 400W and not bigger than 450W.

Here are some benchmarks for the 280x. 

http://www.tomshardware.com/reviews/radeon-r9-280x-r9-270x-r7-260x,3635-18.html

In Metro: Las Light it averages at 207 Watts. That means it likely peaks at the TDP of 250 Watts. 

Here are some benchmarks for the FX8350

http://www.tomshardware.com/reviews/fx-8350-vishera-review,3328-16.html

It averages at 182.21 Watts. 

206 + 182.21 = 388.21 on average from the GPU and CPU alone. 

Now the peak power consumption can be higher than that, and it will be with more demanding games. Basically it depends on the model and the brand of the power supply. There is an Antec supply that my friend is looking at that really can do 550 watts continously but is rated for 500 watts. Meanwhile certain Corsiar supplies are rated at 500 watts and really only output 450 watts continously. Both are highly regarded brands. Nevertheless, if you can consider a situation in which the CPU and GPU can peak within 50 watts of your power supplies rating, then that isn't enough, because that means your PC will shut down at those peaks (there are other components drawing power.) And if you ever were to consider the concept of overclocking (even if you don't think you will now) then you are pretty screwed. And it is all to save $10-$15 (usually the cost difference of 50-100 more watts with the same model.) 

And for you too. I don't use TDP for my calculation. I use tests that measured the power consumption of the whole system at the socket. So when I'm saying the PC will in its whole draw 450 that is not conjecture but measured fact. Taking it at peak efficiciency the system will draw at most 410W directly from the PSU.

I'm not arguing for the sake of a few bucks but more out of principle. An Oversized PSU will always draw more power out of the socket than a perfectly fit smaller PSU. So 500 is good, 550 is still good. 600 will not plunge you into poverty but it's inefficient and so is everything above for this system.