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Windows 7: Power Supply Size Question. (and on USB 2 or 3 usage)

30 May 2012   #1

Windows 7 64bit
Power Supply Size Question. (and on USB 2 or 3 usage)


a. Is a 300 watt power supply sufficiently large for a desktop pc ?

PC would have a single 1 TB hd, and lots of USB ports usage.
No gaming, but lots of videos.

Or, would 400 watts be a lot "safer" ?

b. USB 3 usage very prevalent these days, or USB 2 still most popular and used ?


My System SpecsSystem Spec
30 May 2012   #2

Windows 7 Ultimate SP1 64-Bit

You may want to upgrade later so it would pay you to install the 400w PSU.

As for USB 3, have a look here: SuperSpeed USB 3.0 FAQ
My System SpecsSystem Spec
30 May 2012   #3

Windows 7 Pro X64 SP1

There's no short answer for this. Systems vary a lot.

For example, a high-end discrete graphics card can consume 300W by itself.

Current CPUs tend to max out at 125W, but overclocking can take that to 200W.

Box stock appliance PCs with onboard graphics often ship with minimal PSUs (low 200s to 300W).

As regards USB3, I expect that it's too new to have become more common than USB2. Intel motherboards (Ivy Bridge) that support it without third-party controllers have been on the market for only a few weeks.
My System SpecsSystem Spec

30 May 2012   #4

Windows 7 Home Premium 32-Bit - Build 7600 SP1

If you are going to buy a 300W you might as well get a 500W to cover yourself in the future. The price is not that much different.
My System SpecsSystem Spec
30 May 2012   #5

Microsoft Community Contributor Award Recipient

Windows 7 Home Premium SP1, 64-bit

Quote   Quote: Originally Posted by Robert11 View Post

a. Is a 300 watt power supply sufficiently large for a desktop pc ?
It certainly can be.

My entire PC, including monitor, uses no more than 150 watts under a high load. I don't have a video card.

In normal operation, it uses much less.

I have a 560 watt PSU, way more than I need. I would have preferred to buy a PSU with much less power, but I could not find a high quality modular unit down around 350 watts. They don't seem to be made.

Video cards aside, the trend in power consumption in newer PCs is down, not up.

You should let us know what components you will be buying, particularly the video card. If you are buying a pre-assembled PC from a good OEM, the power supply should be more than adequate.

"Safer" is a function of build quality rather than the sheer number of watts.
My System SpecsSystem Spec
01 Jun 2012   #6

Windows 7 64bit


Thank you all for advice and info.
Nice of you folks to take the time to do so.
Very appreciated.

My System SpecsSystem Spec

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