Building a new system,Opinions please.

[Asmodean]

Actually, a good 400W PSU will handle almost any regular, sensible gaming system (e.g. a 4570K + Radeon R9 280X) for years to come.
Seriously, people tend to massively overestimate a system's power usage and buy either overpriced PSUs that yield no advantage whatsoever or $25 750W PSUs from ebay which equivalate timebombs. If you do not have any definite plans on going SLI/Crossfire, there's no reason to go over 550W.

What about the electrical efficiency. Most power units runs with best "electrical efficiency" when having a workload of 70 to 80 percent.
Your vendor should be able to tell you the specs of your power unit.
So you have to look over the electrical loads and sum up the consumption.
(video card, cpu,...) The total cunsumption should be the same amount as 70/80 percent of the power unit output.

If your system has at a max workload a consumption off e.g. 300 watt (which is realistic looking at your components) with an powerunit which has 80 percent electrical efficency, the total consumption will be 375 watt. (300/0,8=375)

A power unit of 450 watt should do, but with an bigger power unit you have a better electrical efficiency.
Depends on what you are doing with the pc.
If you play resource costing games all day long, most time of the week, you shoud go for a bigger powerunit than 450 watt.
You're just playing frome time to time and work with the pc? Then 450w is sufficient.

why did i post this?

[Luke.]

Rings true, my 470W is currently running my HD5770 and i7 3770 just fine. But the higher is always better as it's not going to remain that way forever if you wish to upgrade.

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[Xenosaga]

Actually, a good 400W PSU will handle almost any regular, sensible gaming system (e.g. a 4570K + Radeon R9 280X) for years to come.
Seriously, people tend to massively overestimate a system's power usage and buy either overpriced PSUs that yield no advantage whatsoever or $25 750W PSUs from ebay which equivalate timebombs. If you do not have any definite plans on going SLI/Crossfire, there's no reason to go over 550W.

What about the electrical efficiency. Most power units runs with best "electrical efficiency" when having a workload of 70 to 80 percent.
Your vendor should be able to tell you the specs of your power unit.
So you have to look over the electrical loads and sum up the consumption.
(video card, cpu,...) The total cunsumption should be the same amount as 70/80 percent of the power unit output.

If your system has at a max workload a consumption off e.g. 300 watt (which is realistic looking at your components) with an powerunit which has 80 percent electrical efficency, the total consumption will be 375 watt. (300/0,8=375)

A power unit of 450 watt should do, but with an bigger power unit you have a better electrical efficiency.
Depends on what you are doing with the pc.
If you play resource costing games all day long, most time of the week, you shoud go for a bigger powerunit than 450 watt.
You're just playing frome time to time and work with the pc? Then 450w is sufficient.

why did i post this?

You got that part completely backwards. Actually, if you measure 300W "power consumption" at the wall and your PSU has an efficiency of 80%, it means that 80% of the 300W (240W) is used by the hardware while the remaining 20% (60W) are heat. That means the electrical components of the PSU actually only have to deal with the 240W for the most part, which further underlines how much we overestimate the wattage requirements of hardware. If Anandtech or so measures the power draw at the wall, you can actually substract 15-20% of that value as mere heat!

Then, this talk about efficiency is actually a pretty moot point in my opinion. Proper PSUs nowadays (80 Plus Bronze or better) have good efficiency values all across the board and fluctuate in low, single-digit percentages (e.g 82% vs 85%).

I'm just stating my opinion on this because I often see self-proclaimed experts go around and spew crap like you NEED 600W MINIMUM to power a generic, single GPU gaming system. It's plain wrong. And this false advice often leads to either paying much more than necessary or buying cheap, dangerous garbage because of a meaningless label (e.g. 600W).
To conclude, all I'm saying is that a 400-550W PSU from a respected brand is the most sensible choice in regards to longevity and money spent. Again, the only exception being that you definitely plan on going multi GPU. However, in my honest opinion, multi GPU is not worth it, especially if you do it later. It involves lots of fidgeting with driver and game settings. But that's another topic.

[lIceColon]

makes no sense to force anyone to do math like that? A psu labelled 400w will provide minimum 400w of power.
Also, the 280x uses 380watts at peak levels and I don't think any 400w psu is going to cover that - even with a 580w gpu you'd be pushing it.

[Xenosaga]

makes no sense to force anyone to do math like that? A psu labelled 400w will provide minimum 400w of power.
Also, the 280x uses 380watts at peak levels and I don't think any 400w psu is going to cover that - even with a 580w gpu you'd be pushing it.

Anandtech measured 393W for the whole system at the wall in Furmark (GPU stress tool, much more taxing than a game). Again, it's an overclocked GPU and overclocked CPU. The unoverclocked 280X goes for 360W.
A good 500W PSU would suffice easily for such a system. 550W if you're paranoid.

[Ichiru]

If you can stretch your budget slightly and order from the US I have this build here


20156 INR without shipping and a lot faster than your current build

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Acolyte of NoMe

[Asmodean]

What about the electrical efficiency. Most power units runs with best "electrical efficiency" when having a workload of 70 to 80 percent.
Your vendor should be able to tell you the specs of your power unit.
So you have to look over the electrical loads and sum up the consumption.
(video card, cpu,...) The total cunsumption should be the same amount as 70/80 percent of the power unit output.

If your system has at a max workload a consumption off e.g. 300 watt (which is realistic looking at your components) with an powerunit which has 80 percent electrical efficency, the total consumption will be 375 watt. (300/0,8=375)

You got that part completely backwards. Actually, if you measure 300W "power consumption" at the wall and your PSU has an efficiency of 80%, it means that 80% of the 300W (240W) is used by the hardware while the remaining 20% (60W) are heat.

Yes, I was calculating backwards. 300 watt theoretical output to 375 watt to the wall using the coefficent. I did some static number joggling only. Its just to get an rough idea, which power unit you need.
Also my calculation is concentrating on a stressed system.

Its just important, if youre playing hardware stressing games often, that your power unit ist not running at 100 percent workload. Thats why I do a little math, before i buy power unit.

Just buy a powerunit between 400 watt und 500 watt and you will be happy.

[matskiuk]

be very careful tho, all this talk about blah blah watts means nothing, if your going to get a decent gpu/graphics card

the watts isnt the big important thing

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[Govedo13]

Wrong. Crappy PSU would not feed your shiny GPU properly with electricity.

During spikes this might even burn the System and in long term it reduces the longevity of the components especially on the GPU. Those measurements are true only if you count perfect laboratory conditions without external heat, bad electricity network and without peaks also Overcloaking is not included.
If your PSU works at 40° C continuously for months instead of lets say the "ideal" 20°C you cannot expect that it would work with the same efficiency.

Also going after qualitative PSU is must. Does not look at the After-Market Label or at the bronze/gold/platinum labelling much but look deeper who manufactured it.
I suggest reading this article:
http://www.tomshardware.com/reviews/powe...,2913.html

The spikes and the OC and the lack of ideal conditions brings the said 20% extra power as a rule of thumb. I personally run 10 years old Fortron PSU branded as 600 W OCZ something even if it is 670 W when I done the measurements. I changed the fan few years ago after it died, other then that I changed like 5 systems since I bought it and I guess it could hold a few more years.

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Official faction players that are often accused of elitism, never deploy them and have those weird, immersion killing "fair fight/dueling" suicidal hobbies. (yes, i've seen enough of those lolduels, where house military with overwhelming force on the field willingly loses a pilot in a duel. ffs.)

[Xenosaga]

He raises a good point. For PSUs, brand names DO matter extremely. I'm from Germany, so you might not know all of them, but these are very highly regarded: be Quiet!, Seasonic and Enermax