How do I know how many watt PSU I need to buy

Question

soon I'm going to start a little company. It's a company/website where a customer can configure their own pc. I am very experienced pc builder, but I never knew what PSU to use best. How do I know what PSU I need to use? Where do I start looking at before buying a PSU for the build. The wattage of volts? or maybe other things

Also: http://superuser.com/questions/167115/how-can-i-check-if-my-system-needs-more-psu-power, http://superuser.com/questions/567294/what-power-supply-unit-psu-is-needed-for-16gb-ram-and-graphic-card-upgrade?noredirect=1&lq=1, http://superuser.com/questions/273365/dimensioning-a-new-psu-correctly?noredirect=1&lq=1, http://superuser.com/questions/287273/which-power-supply-do-i-need-to-support-my-system?rq=1, etc. — Ƭᴇcʜιᴇ007, Jan 13 '17 at 15:15
bear in mind that a 400watt rated supply is for delivering 400watts at a certain efficiency. A 50% efficient supply at 100% load would deliver 400w, but will be pulling 800w from the wall. This means a higher electric bill than an 80% efficient. Many of the better supplies look for 80% efficiency, but the efficiency is not linear across the load%. — Yorik, Jan 13 '17 at 15:16

score 2 · Answer 1 · answered Jan 13 '17 at 14:53

2

You should calculate how much watts is needed for every component.

Example :

CPU = 60 watts

NvidiaGPU = 200 watts

Motherboard = 50 watts

Etc...

Add all that together.

You need to go with good quality PSU's E.g Antec, Corsair etc... True Power

Most systems that include a Nvidia / AMD gpu wont require PSU that is stronger than 750w

Also when you choose an PSU be sure that you choose one with an extra wattage e.g.

If your system requires 600watts than choose a PSU of 650watts.

Hope that answers your question

answered Jan 13 '17 at 14:53

YanivK

84

Thank you for answering my question. I already thought about that, but some components don't have details about how much power their product uses. RAM or a motherboard is a perfect example. Does a RAM module or a motherboard use a lot of power? – DRGN. Jan 13 '17 at 15:36
No they typically don't – YanivK Jan 13 '17 at 15:39
Most motherboards will use up to 50 watts – YanivK Jan 13 '17 at 15:40
It depends on the components that are on-board e.g ethernet, sound etc... – YanivK Jan 13 '17 at 15:41
Most of the components power consumption is listed – YanivK Jan 13 '17 at 15:42

score 1 · Answer 2 · answered Jan 13 '17 at 14:57

1

Where do I start looking at before buying a PSU for the build.

What about https://www.google.de/#q=How+do+I+know+how+many+watt+PSU+I+need, that gives you e.g.

and many many other online calculators?

answered Jan 13 '17 at 14:57

Leo Chapiro

15,599

I know that there are calculators, but it's is for a configurator on my website which i'm programming for right now. Everything has to be done automatic, so not manually. I am thinking to calculate the total use of power of the components and add 50/150 wattage extra to make it more safe that the PSU will guaranteed power up all the components. – DRGN. Jan 13 '17 at 15:41

score 1 · Answer 3 · answered Jan 13 '17 at 15:03

In theory, the PSU you choose should be able to deliver more than the sum of the maximum consumption of every component.

If you want your PSU to live longer, it should even be two or three time that sum.

You should be able to find the power needed by components in their data-sheets (This is easy for CPU or graphic card, but that is not true for some other components).

It's in fact quite difficult to really know precisely before testing the hardware, because not every component vendors gives details about the power needed for their component.

The best way to know without error would be to measure the actual consumption of the running hardware, and multiply this by a factor of 2 or 3.

How do I know how many watt PSU I need to buy

3 Answers3