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250W cheap PSU vs 750W 80+

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March 9, 2012 6:50:24 PM

Hey Guys,

So I have a few questions for you here. First of all, I have an ATX v2 mobo and an ATX v1 PSU... I've seen several posts here that say this setup can work, but it sacrifices the stability of the extra four pins. Can someone tell me what kind of issues I might face with this, if at all? The system is only running a cpu, 3 gigs of ram, 2 HDDs, and 2 fans... So I don't think there would be issues, but I defer to the experts ;) 

Second, as the title states, I'm looking to make the above as low-powered as possible, and I have a few choices of PSUs. The case it's in came with a 250W POS power supply that only has a 20 pin connector on it. I also have this psu laying around that I could use. My assumption is that even though the 750 is 80+ certified, the 250 would be better for me in this case because all I'm looking for is lower power draw. I don't claim to be any kind of expert on this, so any help would be great!

Thanks!

More about : 250w cheap psu 750w

a c 96 ) Power supply
March 9, 2012 7:08:45 PM

This will answer question 1: http://en.wikipedia.org/wiki/ATX
Personally, I would not use a version 1 PSU in any computer; is is outdated!

Regarding the second question. You yourself describe the 250 watts PSU as POS; then why use it? Don't.

Use the 750 watts PSU since you already have it. The computer will draw only the power that it needs, so don't worry about power consumption.
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a c 715 ) Power supply
March 9, 2012 7:11:03 PM

Certainly it will not draw more than the 250 can provide and the 750 although 80+ is not going to be seeing 20% load most of the time so efficiency is not that great for it either. I would use the 250 or replace it with an efficient 300-400watt unit.
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a c 158 ) Power supply
March 9, 2012 7:23:10 PM

If you're not going to install a discrete graphics card, then a good quality 300W PSu is more than enough for your rig. The Antec Earthwatts 380W http://www.newegg.com/Product/Product.aspx?Item=N82E168... has more than enough juice and has a little headroom in case you decide to install a GPU.

A bit of clarification for you...a PC will only draw as much power as it needs to actually run the PC. The rated capacity on PSUs are so you know that your PSU has sufficient rating to power your PC.

If you want to minimize the amount of power that your system uses, then you need to use low power components (you already do this) and a PSU with a higher efficiency rating. PSUs convert AC electricity (120-240V from your wall) into the DC electricity (12V, 5V, and 3.3V) that is used by your PC. This conversion process is not 100% efficient and some power is wasted in the form of heat. In simple terms, a PSU with higher efficiency wastes less power when converting electricity. A good general recommendation is to get a PSU made by a quality mfr with a 80+ Bronze or higher certification.
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March 16, 2012 1:05:26 AM

For some reason I just got notified of the new replies to this thread... Sorry for the delayed response here.

@Rugger
Quote:
A good general recommendation is to get a PSU made by a quality mfr with a 80+ Bronze or higher certification.


So you think I should go ahead and swap out for the good 750 watt I have? I kinda figured that have more available wattage wasn't going to draw more, but you never know :p 
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a c 715 ) Power supply
March 16, 2012 1:21:26 AM

It will not draw more but it will be running at about 20% load.
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March 26, 2012 12:35:07 AM

Best answer selected by zatho.
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