PSU rating too high?

ShiWarrior

ShiWarrior

ShiWarrior

Underboss
Joined
20 Oct 2002
Posts
33,642
Location
Oxfordshire / Bucks
Hi all

I came across a video on YT which talked about power supplies, i did not realise that that a PSU rating of say 1000W and your system running at say a max wattage of 400 meant that its not running at its most efficient state

i originally thought that a good quality PSU and a higher the wattage rating was better, but it is not the case ?


so onto my question, i have just bought a Power meter thing that my Computer is now plugged onto, and I ran 3D mark bench and I hit a maximum of 260W

Is there any other tests I can do to see if it would go any higher ?



I have a 5 year old (i think) 780W in my system, would it be worth while me changing the PSU to something like a 300W ?

I haven't tried overclocking my system yet, and I have to sort out my "air flow" so i could be adding more fans to the mix

Specs :

i5 Skylake 6600K
Msi Gaming pro motherboard
16Gb RAM
GTX 970

currently 2 HDDs and 1 ssd
1 DVD ROM
27" screen running at 144HZ at 1080p (i have a 2nd screen but not hooked it up for the above test)
 
ShiWarrior said:
I came across a video on YT which talked about power supplies, i did not realise that that a PSU rating of say 1000W and your system running at say a max wattage of 400 meant that its not running at its most efficient state
Click to expand...
Difference is at least equally big during most of the time PC is powered: In idle.
Depending on use there might be easily 5+ hours of idle/low load per every hour of gaming.

Don't really remember any quality PSU having 780W rating so your PSU is also likely some older effiency class cheap PSU.
Before 80+ Titanium there hasn't even been any efficiency requirement for below 20% load.
And that PC likely idles at around 60-70W power draw.


450W would be enough.
But that's class where there aren't much of quality PSUs available.
https://www.overclockers.co.uk/bitf...plus-gold-modular-power-supply-ca-229-bx.html
https://www.overclockers.co.uk/seas...plus-gold-modular-power-supply-ca-019-ss.html
For little more than that G-450 there's new Focus+ 550W with 10 year warranty.
https://www.overclockers.co.uk/seas...plus-gold-modular-power-supply-ca-05p-ss.html

Though in efficiency 80+ Titanium PSUs beat even "better sized" 80+ Gold PSUs with for example Seasonic Primes pulling nearing 90% efficiency at 5% load.
http://www.tomshardware.com/reviews/seasonic-prime-850w-titanium-psu,4761-5.html
 
thanks for your reply, dont fully understand the ins and outs of power supplies, but do you think its worth me changing ?

there was a deal on the OCZ 780W PSUs that Gibbo was doing (before the standard of 80+) and i was building a new system then, and was in need of one

i was looking at this PSU (heard good things about Super Flower)
https://www.overclockers.co.uk/supe...us-platinum-power-supply-black-ca-055-sf.html
 
The reason to avoid an oversized PSU is that it could waste electricity. Buying an entire new PSU costs more than any amount of electricity saved though, so no, it's not worth it.
 
ShiWarrior said:
yeah i think that's the one !

i haven't experienced any problems with it over the many many years I've had it
Click to expand...
Obvious symptoms are mostly the safer ones.
From its age it surely doesn't have assembly flaws like weak solder joints and it's up to how long capacitors last.
Unfortunately capacitors don't give guaranteed signs before of failure.
Decreasing capacitance/increasing ESR from aging and wear starts increasing ripple, which can at some point start to wear down PC's components before clear symptoms appear.

Though that oversizing has helped.
 
EsaT said:
Decreasing capacitance/increasing ESR from aging and wear starts increasing ripple, which can at some point start to wear down PC's components before clear symptoms appear.

Though that oversizing has helped.
Click to expand...

wear down the components BEFORE symptoms appear ?
i think i'll start looking for a new one then, i got a Skylake system a year ago, certainly don't want this to go up in smoke as they say !
 
ShiWarrior said:
wear down the components BEFORE symptoms appear ?
Click to expand...
ATX specification sets 50 mV limit for ripple in 3,3&5V and 120 mV in 12V and PC's components should be designed to take that into account.
Obviously they also tolerate some amount of higher ripple, but increase of ripple always adds to stress of VRMs of CPU and GPU shortening their lifespan.
And the more clearly ripple is below those limits the better for PC's components.
Because of ripple measuring old PSU should include oscilloscope instead of just checking voltage using multimeter.
Though high end multimeters could start measuring some of that AC-component...

PSU's design likely has some effect to when wear of capacitors starts causing voltage stability problems with clear symptoms like crashes.
And stronger VRM of high end motherboards/graphics cards likely tolerate higher ripple without obvious symptoms.


That Superflower is definitely well priced for 80+ Platinum PSU.

From more common 80+ Gold PSUs Seasonic Focus+ is very well priced high end PSU.
https://www.overclockers.co.uk/seas...plus-gold-modular-power-supply-ca-05p-ss.html
 
Disco_P said:
Either of these will do you right. You can choose the extra capacity or extra warranty. You might also have an aesthetic preference (I know that @pastymuncher has a strong opinion on the superflower lighting :D)

My basket at Overclockers UK:

Total: £169.90
(includes shipping: £0.00)



​
Click to expand...


cheers

what about going to the Platinum versions of these ?
 
Unless you have been running 24/7 don't worry too much about cap ageing.

Also don't worry too much about efficiency at load levels below 20%, because if you only using 50-150 W dropping 5% in efficiency is only going to waste 2.5-7.5 W which is nothing.
 
You must log in or register to reply here.
Back
Top Bottom