PSU's are confusing me!

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DaddyBradley

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Feb 12, 2014
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First and foremost... This place is great! First post here, but been doing quite a bit of lurking and reading.

So I'm building my first PC. (Seems to be a lot of that going around.)

What I got so far.

HAF 912 (200mm in front, and top)
I5 3570K
Asrock Extreme4
G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-2133

GPU still in the works. Another few weeks prolly. (Taking suggestions)

Now... the PSU. I already have an Antec 380 Earthwatts laying around.
When I use the "estimated power usage" calc on pcpartpicker, it says I'm only at 166W.

Even if I add a GeForce 660, it only pushes it up to 306W...

So how far can I expect to get with this Antec? I'm sure its safe until I add GPU, but is the 306 getting too close to the 380??
 
Solution
ubercake


Check system and GPU power consumption on review sites such as Tom's for those cards in which you might be interested. I always just throw something like this out in my favorite search engine:

GTX 660 review

I consider a few sites reputable (Tomshardware, guru3d, techpowerup, anandtech) based on what they say...
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MurrayA

MurrayA

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With that kind of setup its best to go for a PSU around 500 - 600 watts

the Corsair CX500 id a great PSU and quite cheap

as for a graphics card, i would recommend going for a GTX 770, but the 760 will be fine
 
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ubercake

ubercake

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Oct 28, 2009
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You can run a 660 on that PSU with that system. You have a total of 336W available on the 12V rail with that PSU and a system with that GPU requires around 312W under load:

http://www.tomshardware.com/reviews/geforce-gtx-660-geforce-gtx-650-benchmark,3297-23.html

The GTX 660 requires around 11A of power from the two rails available on that power supply which are 17A and 15A.

You'll be fine with a 660 and that PSU if you don't overclock anything. Also, something to consider is PSUs usually operate closest to maximum efficiency close to 100% load. This 80-plus bronze PSU should work well with no OC.

On the other hand, if you even slightly overclock the CPU or GPU, don't consider operating with this PSU.
 
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ubercake

ubercake

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Most people will cite the recommended wattage as expressed by the GPU manufacture though the GPU manufacturer is trying to cover themselves and reduce returns in the case where people use poor-quality or bargain-bin power supplies in their systems and can't power a system with their low-quality poorly-designed PSU. They do this by saying 'Power requirement: 600W'. This is why Tom's Forum is good. If you can learn a little bit about exactly what is required of a power supply (Amps available on the 12V rail and total Wattage on the 12V rail(s) are of the utmost importance with most modern systems), you know what to look for and can get the real wattage you're after. You no longer have to overpower your PC when you understand some of the basic concepts about power requirements and power supplies.
 
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photonboy

photonboy

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Hi,
First of all, I recommend a quality 500W PSU with your setup and a GTX660.

*Here's a good rule of thumb-> If the Power Supply has the proper 6/8-pin PCIe connectors for the graphics card it should work. For example, most 450W PSU's have only a single, 6-pin PCIe connector. A GTX660 might need TWO of these (haven't checked).

TOTAL WATTAGE:
Just because you have a "350W" PSU doesn't mean it can output 350W. That number is created by adding up INDIVIDUAL outputs under load. Some of them might do 300W only. Plus, there are different Voltages so if you don't use the max 5V Wattage you can't get more out of the 12V outputs.

Other:
It's also not a good idea to run a PSU near its maximum output anyway. It reduces life expectancy, and can affect the quality of the output. Fan noise also usually starts to rise after the 50% load point.

*I recommend buying a PSU so that you achieve about 60% load.

My advice is something like THIS:
http://pcpartpicker.com/part/antec-power-supply-neoeco520c
- 1x8/6-pin, and
- 1x6-pin
(supports up to 1x6 + 1x8-pin PCIe on graphics card)

I'd personally spend even a little more, but this one is pretty good value. Again, if the PSU doesn't even have the proper 6/8-pin connectors it won't even work without adapters (which I don't recommend).
 
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DaddyBradley

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For my GPU, the 660 is certainly not set in stone. My main goal is to keep it at or under $200.

ubercake - I sure wish I understood all that a little better! Being such a noob, I dont plan on OC'ing in the beginning. I want to get a bit more comfortable inside a computer first. However, it sounds like you think my Antec will be sufficient. As long as nothing is OC'd, how do I know which GPU's I can comfortably shop for?
 
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4745454b

4745454b

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Apr 29, 2006
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A stock/normal 660 needs only one 6pin PCIe plug. I agree that the 380W should work fine for the 660. Anything higher then the 660/7850 however will need a new PSU. (or if you want to OC.) I would figure out what GPU you will be running before deciding if you need a new PSU.

PSUs usually operate closest to maximum efficiency close to 100% load.
Click to expand...

Slightly disagree. At 100% output there is normally a slight drop off compared to 50-80% load. Quality units will run 1-2% less efficient at this load. The junk units you correctly pointed out in your second post will drop off a lot, IF they can even hit their 100% output. I usually try to get 80% load as the idle efficiency will be much better.
 
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rolli59

rolli59

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GTX660 none Ti only one PCIe 6 pin power! http://www.geforce.com/hardware/desktop-gpus/geforce-gtx-660/specifications
 
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ubercake

ubercake

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Check system and GPU power consumption on review sites such as Tom's for those cards in which you might be interested. I always just throw something like this out in my favorite search engine:

GTX 660 review

I consider a few sites reputable (Tomshardware, guru3d, techpowerup, anandtech) based on what they say and consistency with my personal experience. I look for consistency in what they have to say. When it comes to power, I find the highest number of watts listed among the sites and use that as a guideline even though most of the systems in which the tests are conducted use OC'd CPUs to eliminate any possible CPU bottleneck's affect on GPU performance. Personally, I like a little more wiggle room in available wattage because I'm constantly upgrading my gaming PC, especially, and like to have a PSU ready for my next upgrade no matter which GPU(s) I choose.

As for now, your current PSU will be sufficient with that system and a GTX 660 with no overclocks. It has a 6-pin PCIe power connector so you won't need a molex-to-PCIe adapter.

You will need a lot more wiggle room when it comes to overclocking your system because you can't exactly calculate the power requirements when you start messing with it. I'm sure some EEs could precisely calculate things, but even they can't predict the exact power or heat max of your CPU when it comes to overclocking; luck of the draw with CPUs or anything you want to OC for that matter. When you decide to overclock, consider getting a new PSU first.
 
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Solution
MurrayA

MurrayA

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Could use one of these

http://www.amazon.co.uk/Molex-Express-Graphics-Power-Cable/dp/B000KU3QD8
 
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DaddyBradley

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DONE AND DONE! I can't believe y'all helped me get that squared away so fast... never even had to leave the comp!

Thank you all for your helpful comments, and for being patient with me!
 
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ubercake

ubercake

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I think this is a good rule to follow, too. Usually when the PSU has the power you need (and it is a newer high-quality PSU), it will have the PCIe connections you need.
 
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