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Discussion Starter · #1 ·
Right, if I was to upgrade to a bigger PSU, in what way would my electric bill increase? Would the PSU consume the same electricity as my current one, or would it use more?

I'm wondering if instead of upgrading to a 750W, I would be better off upgrading to a 1000W, but don't want to pay for electricity I won't use until future upgrades...
 

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From what I've read, using a smaller percentage of the available PSU Wattage will result in higher efficiency.

So if your system uses 700W a 1000W PSU will save you on your electric bill vs a 750W PSU.. but as for it being worth it over the long run I can't say the extra cost is worth it, depends on your system, electric bill and how long you have it for, etc.

Edit: Most likely the difference in efficiency won't be worth it.
 

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Getting a more efficient power supply will lower your electric bill, even if it's rated for a higher wattage. The system will not pulls more wattage then it needs, so even if you get a 1000w unit it will still only pull around 300w.

If you are looking for a really efficient power supply I'd suggest the Seasonic X-650. It's a very high quality unit.
 
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Fortunately, there are only 2 things that have to be worried about when concerning the electricity bill:
  1. The actual power draw of the rig.
  2. The efficiency of the PSU.
As long as the PSU is capable of providing the power that the sig rig needs, it doesn't matter what it's rated for. So, if you were to use a 1000W unit for a rig with a simple rig that has a single 9800 GT, then it wouldn't draw anymore power from the wall than if that system had a 400W PSU powering it. Actually, it might differ slightly due to the efficiency, but the difference would be very small.

So when shopping for a PSU, going with a PSU that is capable of supplying "1000W" won't result in a higher electricity bill than using a PSU that's capable of only supplying "500W". But what does increase the electricity bill is upgrading the system so that it needs more power.
 

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You want an 80+ Gold PSU, but you also want a motherboard that can be tweaked for efficiency as well.
 
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Quote:


Efficiency

The efficiency of a power supply unit is the percentage of total output DC power in relation to total input AC power. The portion lost during conversion is mostly in the form of heat.

This index directly relates to your power bills. For example, if your computer system consumes 300W of power, using a PSU with 85% efficiency will require about 353W input power, and a 70% PSU will pull 428W power from the wall. It is not hard to know how much more money you are going to pay using a low efficiency power supply, and this number will typically grow as time goes by.

A power supply with a higher efficiency rating will not only help save costs - the heat dissipated will be much lower as well, resulting in better reliability and durability, and can also help reduce noise as its cooling fan can operate at lower speeds and still provide adequate cooling. from newegg

you might consume less electricity with a more efficient PSU.
 

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Quote:


Originally Posted by Crash.Forelli
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you might consume less electricity with a more efficient PSU.

/thread.
 

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Quote:


Originally Posted by otterpopjunkie
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From what I've read, using a smaller percentage of the available PSU Wattage will result in higher efficiency.

Not quite true. PSUs have an efficiency curve. The efficency tend to be lowest at the minimum and maximum ratings. Peak efficiency is usually in the 40-80% range.



Quote:


Originally Posted by TwoCables
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So when shopping for a PSU, going with a PSU that is capable of supplying "1000W" won't result in a higher electricity bill than using a PSU that's capable of only supplying "500W". But what does increase the electricity bill is upgrading the system so that it needs more power.

Actually, it can depending on your load. A 500w PSU would probably use less power on 300w system than a 1000w PSU on the same system. However, we're talking about a few percentage points here. Nothing that's too noticeable monthly... $1 maybe.
 
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Ive just purchased a new PSU myself so did some research on the PSU's that interested me... it seems from everything Ive read that a unit is at its most efficient when being used at 50-70% of its rated capacity... so it would seem that bigger is indeed better! (errmmm... to a point at least!) Most reviews you read on any PSU your interested in will tell you a little something on the efficiency an at what stage in the "power band" it starts to drop off.
 

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Discussion Starter · #11 ·
Ok, thank you everyone. REPs all round. (You too Duckie.
 

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I wish I could remember who did this mass review I'm thinking about (I think it was tomshardware), but in the efficiency tests they really fell off under 15% or so load. One power supply dropped so bad it couldn't maintain its 5v line (it fell to what, 3 and a half or so) in one low-power test as it was designed for a PC that idled with much more current.

There is such a thing as too big. This 750 I have is almost too big for my computer IMO because I barely draw over 100 watts at idle, although it is far superior to the Antec 550 it replaced that self-destructed as that unit took another 20w at idle and 100+w at full load. Heck that thing went to 400 watts once at 3.6Ghz cpu+gpu occt test [that may have killed it]. The same test on the new one drew what, 290w or so.
 
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