Calculating PSU power needed

edhunter

Dear All, I need to decide what is the power needed for my system.

I have been looking around couple of websites to calculate the power needed and each gave a different power rating, ranging from 450-760...

So I decided to calculate it manually. So below is the list of hardware and estimated max power drains from different websites.

CPU:(3770k) 115
GPU(7950) 200
coolers (CPU+4) 25
HDD(1TB) 10
SSD(120HX) 5
DDR (16Gb) 40
Mobo(GA UD5H+WB) 200
Optical drive 25
620
25% aging and overhead 827

The Mobo power drain is the grey area, I know it has couple of on-board features that might draw some power like the: WB, soundcard...etc but am not sure 200...

I would like to know is 850W an overkill for this system and where did I miss something or overestimated drain?

thanks,
Ed

AvoK95

This thing can run on a 500W PSU. but would recommend something a bit more, for durability. Like a 750, 850W. Because you can easily crossfire two of the same card and OC without a hiccup.

edhunter

Thanks for the reply. What you say about XFX 750W? or you have any other option in mind in similar price range...around 115$+vat.

AvoK95

XFX has the best power supplies in the market. Run for it! And may I ask who's selling them?

edhunter

Compuworld Dekwaneh.

yasamoka

Mobo consuming 200W of power? DAMN. No way dude. That thing sips at most 25-50W (to the lower number if it's not an enthusiast board with a load of PLX, SATA, USB3.0 mucrocontrollers and such).

The i7 3770K draws 77W at full load if not OCed. OCing without a voltage increase increases power draw linearly with frequency (a bit less, as some parts in the CPU draw power but do not get OCed, like memory controller). With a voltage increase, you'll looking at an increase in power consumption squarely proportional with voltage increase. 115W / 77W = 49.35% extra power draw.

OCing your 3770K from 3.5GHz to 4.6GHz increases power draw by 31.43%. a 6.6% overvolt would get you to 115W.

Obviously, higher clocks with much higher voltages would spin the power consumption of that thing way out of these figures, and the gains will be minimal.

edhunter

Thanks yasamoka for the details. I tried to put the max power that the components would draw. So 115 W for the cpu is fine i guess based on your explanation. The mobo I was hesitant of the value. I got it off a website, which was comparing mobo's power drains,but was not quite sure what is the calculation based on and since this board ranked the second most!

WaficLawand

Hi is 500w psu enough for

core i5 3570 3.4ghz
8gb of ram
hd 7850 (gpu)
1tb hdd
any optical drive

AvoK95

WaficLawand wroteHi is 500w psu enough for

core i5 3570 3.4ghz
8gb of ram
hd 7850 (gpu)
1tb hdd
any optical drive

500W is enough. But if you don't have a power supply yet consider getting a 550-600W or above. However if you're on an extreme budget. Get the Elite 350 that comes with a 500W PSU.

WaficLawand

Oh yeh thanks I bought the elite 335u which comes with 500 w psu