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Can too much power be bad?

E

eshell1

n00b
Joined
Nov 10, 2007
Messages
15
Essentially, I have a 550w PSU working great with my current setup. However, I now have an 850w PSU of equal quality still in the box, but I am unsure whether to sell it or use it. Can too much power be harmful?
 
No, because your PSU should only be supplying however much power you need, not it's max rating. :)
 
Bad in the fact that higher wattage PSU's have lower efficiencies. You'll be using more energy to deliver the same amount of power.

Let me go a little bit further...For the same system, higher wattage PSUs will have lower efficiencies because efficiencies are better when you're closer to the peak output of your PSU (but if you're very close, efficiency drops again).

http://www.silentpcreview.com/article276-page1.html
 
eshell1 said:
Essentially, I have a 550w PSU working great with my current setup. However, I now have an 850w PSU of equal quality still in the box, but I am unsure whether to sell it or use it. Can too much power be harmful?
Click to expand...

What exactly are the PSU's?

I say sell the 850W, get some cash :)

A decent 550W should last a one card set-up a good time.
 
CoW]8(0);1031647938 said:
Bad in the fact that higher wattage PSU's have lower efficiencies. You'll be using more energy to deliver the same amount of power.

Let me go a little bit further...For the same system, higher wattage PSUs will have lower efficiencies because efficiencies are better when you're closer to the peak output of your PSU (but if you're very close, efficiency drops again).

http://www.silentpcreview.com/article276-page1.html
Click to expand...

efficiency peaks are different from every PSU. Some PSUs peak at 80% their output, some at 40%. Its just all over the place. Of course, this goes out the window if your on a brownout. And of course, some PSUs at there worst are more efficient then some PSUs at there best.
 
CoW]8(0);1031647938 said:
Bad in the fact that higher wattage PSU's have lower efficiencies.
Click to expand...

Incorrect generalization FTL!

There are MANY higher wattage units that are significantly better efficiency than many lower wattage units. We don't know what the OP is using for a 550W or 850W so we can't assume anything.

In the article you link, the two "higher output" power supplies that are used aren't exactly known for having good efficiency. In fact, they're generally pretty bad. Essentially they're making a comparison between an H2 and a Prius. There are high wattage power supplies that easy mantain between 80 and 85% efficiency typical.

And to use your own argument against you.. have a look at the link and a look at the SP450W. It's only a 450W power supply, yet the Seasonic 600W is more efficient than it is across the board.

The only accuracy in your statement is that there are some higher wattage units that are actually considerably lower efficiency (compare to their best efficiency) at lower loads. But without knowing the OP's 550W or 850W units, because all units are different, you still can not make the assumption that their 850W is going to be less efficient than their 550W.
 
And on another note, this is why you'll see many people recommending MORE than someone will need for "future/upgrade purposes". It's usually better not to run a power supply at it's bleeding edge output, although w/ a quality unit that's going to be less of an issue. Power supplies tend to be most efficient somewhere in the middle of their power output (ie: ~50-75%), but it's not *always* true. And w/ the 80plus initiative that so many are jumping on, there's even less variation, at least w/ the better made PSUs out there - they need to do 80% across 20%, 50% and 100% output levels.
 
jonnyGURU said:
The only accuracy in your statement is that there are some higher wattage units that are actually considerably lower efficiency (compare to their best efficiency) at lower loads. But without knowing the OP's 550W or 850W units, because all units are different, you still can not make the assumption that their 850W is going to be less efficient than their 550W.
Click to expand...

If we take the statement that they are similar quality, the curve of efficiency during load (which I believe was CoW]8(0)'s main point) the 550W would probably have better efficiency.

Of course if he would just tell us what the models were, then this wouldn't be a problem. :rolleyes:
 
Hazaro said:
If we take the statement that they are similar quality, the curve of efficiency during load (which I believe was CoW]8(0)'s main point) the 550W would probably have better efficiency.
Click to expand...

Even if they're similar "quality" that's not true. If they were similar design, that might be true, but often times the same design can not transcend across different output wattage capabilities and different platforms are used.

Hazaro said:
Of course if he would just tell us what the models were, then this wouldn't be a problem. :rolleyes:
Click to expand...

Thank you. ;)

We could be talking about an in-efficient Ultra X2 vs. a highly efficient CWT built Gigabyte Odin or Thermaltake Toughpower. If that were the case, the CWT is more efficient across the board.
 
Well, I ask because i'm upgrading to SLi in a couple of weeks (dual 8800GT's, or whatever is out at the time). In this case, should I got with the 850w?

Also, on a side note, when overclocking my processor even the slightest bit, I get the blue windows screen crash. I know that it isn't overheating, as the processor runs at about 38 - 45 C. Could it be that overclocking is demanding too much of my PSU?

By the way, the models are:

550w: Rosewill Performance Series RP550-2
850w: Rosewill Xtreme series RX850-S-B

Sorry bout being so vague, I'm a big noob.
 
jonnyGURU said:
Even if they're similar "quality" that's not true. If they were similar design, that might be true.
Click to expand...

Took one thing for another.

eshell1 said:
Well, I ask because i'm upgrading to SLi in a couple of weeks (dual 8800GT's, or whatever is out at the time). In this case, should I got with the 850w?

Also, on a side note, when overclocking my processor even the slightest bit, I get the blue windows screen crash. I know that it isn't overheating, as the processor runs at about 38 - 45 C. Could it be that overclocking is demanding too much of my PSU?

By the way, the models are:

550w: Rosewill Performance Series RP550-2
850w: Rosewill Xtreme series RX850-S-B

Sorry bout being so vague, I'm a big noob.
Click to expand...

Rosewill been stepping up after their one good lower PSU?

http://www.jonnyguru.com/review_details.php?id=122&page_num=4

I'm sure someone can give you insight on that 550W of yours.
 
Prime example right there... Both of those Rosewills are built by ATNG, but the "Performance" is built more for price than the "Xtreme." The Xtreme is a much better unit over all.
 
eshell1 said:
....
By the way, the models are:

550w: Rosewill Performance Series RP550-2
850w: Rosewill Xtreme series RX850-S-B...
Click to expand...

EEEEEWWWWWWWWWWWwwww

keep those things AWAY from the 8800s! Not doing so would be considered crimes agasint humanity!

Rosewill makes decent cases. Everything else I have to say about them is negative, as I'm sure is also true for everyone in this thread including jonny (who has a psu reviewing site btw)

edit: oh well apparently rosewill has been up to some good.... who'da thunk it. I didn't know it was possible....

for your two 8800s your gonna want something with at least 40A on the 12V(s), which would probibly be around a 650/700W PSU. Cant go wrong with seasonic's M12, they perform very well but are very expensive. A toughpower is a nice choice, but at idle its still producing 50mV ripple which isnt exactly "excellent". A corsair 750W would be a good fit. A PC power and cooling silencer would be a good fit, but, contrary to the name and to quote jonny (actually it might have been Paul): "It doubles as a leaf blower at full load". I was gonna say the new antec Quatros would be good cheap units, since, well they dont perform as well as some previously mentioned PSUs but... they Quatros also arn't cheap :confused:. Also, I've never worked with one personally but a higher wattage FSP would be a good value PSU again.

A couple to stay away from are the OCZ StealthXStream and even the higher end GameXStream. And uhh, well, generally any 700W psu going for under $120 can't be such a great idea, although I can't think of any spicific units right now....

and I have a question for jonny thats kinda off topic: in your testing, do you generally (very generally) find that lower efficiency PSUs run hotter and louder then higher efficiency ones? I mean it makes sense logically, the lower the efficiency the more power used up inside the PSU the more heat released by the PSU, but I'm wondering if that logic is prehalps lost in the details or if it holds true.
 
Hazaro said:
Or you could of quoted me ;)

I was considering getting one of their lower watt PSU's, since it was getting good reviews, but went with the Corsair.
Click to expand...

Be glad you didn't, and take it as a lesson you didn't have to learn. Just because a company has a good product doesn't make them all good, and just because a company has bad product doesn't make them all bad.

For example: The Rosewill PSU's that come in cases and those that are made by Solytech I still wouldn't touch with a 10 foot pole.

Only the Xtreme really stands out and I've see that exact same PSU make the rounds under many different brands in EU already.
 
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