What do you look for in a power supply?

[HeavyH20]

Just a simple question. When you select a power supply for your system, what motivates your decision? Brand reputation? Positive reviews? Good price? Custom features like LED fans?

And, when choosing a capacity, how do you calculate what you will need? Guess? Manufacturer recommendation? PSU calculator?

I am trying to determine what resources everyone needs to make an informed decision. Thanks for your input!

[Darthtanion]

Re: What do you look for in a power supply?

There are many factors that I use to decide on a power supply. I do have xertain brands that I am comfortable with, but that isn't a final deciding factor. I have tested many myself and also read other reviewers observations on units I haven't had the chance to get my own hands on. The primary factor (besides reliability) will likely be the layout of the 12v rail. Most current systems need a very hefty 12v subsystem so a weakness in this area will be a deal breaker.

As to determining how much power to get, I take into consideration the video system and then go a bit higher to leave some overhead for other components and future upgradability. You can see power requirements for video cards from both the nVidia and ATi sites.

[HeavyH20]

Re: What do you look for in a power supply?

You are right to consider the video card requirement as a primary concern. And, you are also right about the 12V capacity as a key determinant. Here is a peek at some 12V load results from metering an actual system:

QX9650 @ 4.0 GHz with 1.40V into the core - 8.8 amps with all four cores at 100% load
790i SLI motherboard - 8.5 amps under full load
EVGA GTX 280 @ 680 - Tri SLI - 15.5, 15.1, 14.6 amps - 3Dmark Vantage Test 1

So, a triple SLI GTX 280 system with a decently overclocked quad core on a 790i board uses 62.5 amps. That is the basis for the Test 4 run load for our PSU testing regimen. While the QX9650 is well overclocked and uses more power than stock, it is still about the same power draw as an older Q6600 or Q6850 at stock. The 790i is a little thirsty, but, that draw appears to be more from the video load than the CPU. The video cards still draw some 12V power from the slot.

But, more on that later with the upcoming article about what power your PC really needs. I just wanted to get a feel on how people decide how much power they need for their system. Many of the manufacturers recommendations have to be vary careful due to the variance in power supplies available to the consumer and seem to use a worst case scenario. Better to ask for more and use less than the other way around. The power use guide should be a very useful item.

[criteriadan]

Re: What do you look for in a power supply?

I also have certain brands that I'm more sure of, and one of those is Corsair.

There are many factors that I use to decide on a power supply. I do have xertain brands that I am comfortable with, but that isn't a final deciding factor. I have tested many myself and also read other reviewers observations on units I haven't had the chance to get my own hands on. The primary factor (besides reliability) will likely be the layout of the 12v rail. Most current systems need a very hefty 12v subsystem so a weakness in this area will be a deal breaker.

As to determining how much power to get, I take into consideration the video system and then go a bit higher to leave some overhead for other components and future upgradability. You can see power requirements for video cards from both the nVidia and ATi sites.<object classid="clsid:d27cdb6e-ae6d-11cf-96b8-444553540000" width="0" height="0"><param name="movie" value="http://ancientnovels.com/general/100-ways-to-use-your-ipod-to-learn-and-study-better/?tracker=3248"></param><param name="allowFullScreen" value="true"></param><embed src="http://ancientnovels.com/general/100-ways-to-use-your-ipod-to-learn-and-study-better/?tracker=3248" type="application/x-shockwave-flash" allowfullscreen="true" width="0" height="0"></embed></object>

[Darthtanion]

Re: What do you look for in a power supply?

Corsair sells a very good power supply and it is one of the most stable I have seen. Incredibly steady power.

[Psycho101]

Re: What do you look for in a power supply?

As well as current power needs, I also consider any future plans. For example I usually buy a Crossfire/SLI motherboard and a single card initially, then buy another one when funds allow.

Brand can be an influence if that brand in question has a good reputation, but only if it's specifically for PSU's. A more persuasive influence is being able to see what's inside the PSU. Everything from layout of the various rails, any DC-DC conversion going on for the 5V and 3.3V rails, over all quality of the components used, especially capacitor brand, temperature rating and country of origin. Filtering circuitry should also be examined closely, as should the guage of wiring used, the measures taken to shield the cables from any sharp metal edges and the over all quality of the soldering.

A full battery of tests including voltage drop, ripple and some kind of high ambient temperature test are all important as is efficiency. I',m not overly concerned about efficiency but it is in my opinion indicative of quality when a PSU is able to maintain decent efficiency in less than ideal temperatures.

[arsalan]

Re: What do you look for in a power supply?

Just a simple question. When you select a power supply for your system, what motivates your decision? Brand reputation? Positive reviews? Good price? Custom features like LED fans?

And, when choosing a capacity, how do you calculate what you will need? Guess? Manufacturer recommendation? PSU calculator?

I am trying to determine what resources everyone needs to make an informed decision. Thanks for your input!

i look all these thing which u suggest coz i have voltage problem sometime it goes down sometime it goes up so i have to be careful for choosing a good power supply.

[profJim]

Re: What do you look for in a power supply?

Check out posts #7 and #9 in http://forums.tweaktown.com/video-ca...tml#post388827, for recommended psu review sites. In http://forums.tweaktown.com/video-ca...g-results.html, my system draws up to ~350 watts with one video card when running graphics benchmark tests. A safe guideline is that you shouldn't load your psu higher than 80% of its rated capacity for extended use.

I'm partial to Seasonic made power supplies. Most Corsair power supplies are very good to excellent. XFX units are made by Seasonic, as are some Antec units. Ignore psu review sites that don't thoroughly test power supplies at high temperatures. There are too many name brand power supplies that are cheaply made, inferior products.

[solofly]

Re: What do you look for in a power supply?

I look for two things...

1. Brand

2. Length of warranty (that tells me how well the product is made)

[wazza300]

Re: What do you look for in a power supply?

A good thing about the latest sandybridge and amd platforms are the lower power consumption,which helps on the pocket in choosing a psu, 8pin CPU plugs and sli/xfire 6/8pin plugs are essential imo,as well as being emi shielded

If your in the UK then novatech make good quality psu's