Quality PSUs, how much is considered enough overhead

MrWhippy

MrWhippy

MrWhippy

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Talking about decent branded PSUs.

How much overhead do people generally consider adequate?
I mean "to be on the safe side", not for future upgrades etc.

Or to put it another way, for example, how close to a given Wattage rating PSU (decent make) would people be comfortable going before they decide a more powerfull PSU is in order? Within 20% / 33% / 50% of the stated value?
 
if a PSU is pushed too close to its rating, it gets too hot and the fan spins up making lots of noise.

i am sure i seen mentioned that its best to run a PSU at around 50-60% load where its most efficent
 
I try and go for about 25% more than needed, my psu is on the edge of me being comfortable drawing 300w on a 400w OCZ Psu.

Your better buying something your going to be running reasonably close to its limit as where thats where its efficiency, however whe I replace mine I'll go for the biggest I can afford as PSU and case tend to be carried over through multiple builds.
 
See what I'm trying to get my head around is this...

I've got a rig that's getting a bit long in the tooth (skt939, X2Amd3800, 1Gb, ATI 4670 etc) and will be getting an upgrade, but I'll likely do the upgrade in stages as funds permit.

But I reckon I can probably get at least part way through a rolling upgrade on the current PSU (Seasonic 430Watts). Just trying to work out if I could say swap out the GFX for something like a 5850/6870/6950 and still be ok for now. Or possibly I might start at the other end and do the CPU/MB/RAM first.

Any thoughts welcome, last thing I'd want to do is blow new kit, but then as the upgrade is likely to take several months to complete I want to get the max usage out of the stuff I already have.
 
I run 2 5850 in crossfire in my system in sig and was pulling 430w from the mains with Prime and 3d win mark running together and my system now pulls 500w with prime and Furmark running.
 
New CPU/motherboard/RAM should draw less power than the old stuff. I'd start there, then do the PSU, then the GFX.
 
Cleeecooo said:
I like to have about 25-30%
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+1 on that, pc compoment are usaly recormended a minimal more then what would acculy be the minimal you could put it on, plus the overhead of about 25-30%, this will make your PSU be at 50-60% tippicaly, where they are most effective (most PSUs are anyways)

and also gives enought room for a 2nd without the need of replacing the PSU
 
would you guys says i'be be okay running a i5 2500k and 2 6950's on a corsair TX 650? And would i be able to push it to to 6950's unlocked to 6970's?

and what if the PSU blows and ruins my pc? what does the psu manufacturer do? i doubt they cover the cost of the pc?
 
wentalong said:
would you guys says i'be be okay running a i5 2500k and 2 6950's on a corsair TX 650? And would i be able to push it to to 6950's unlocked to 6970's?

and what if the PSU blows and ruins my pc? what does the psu manufacturer do? i doubt they cover the cost of the pc?
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You should just about be fine but i would get another PSU if you plan any overclcoking at all.

If ur PSU takes everython with it then just RMA allthe parts seperately. The PSU manufacturer wont cover ppl taking risks/ignorance.
 
yeahh, im not sure, i think i saw some sli crap on the box, im not sure, but its a single 21v rail with 51amps i think,but im guessing that 850watts is the sweet spot for psu's at the moment?
 
wentalong said:
yeahh, im not sure, i think i saw some sli crap on the box, im not sure, but its a single 21v rail with 51amps i think,but im guessing that 850watts is the sweet spot for psu's at the moment?
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i would have personly gone for the 750watt one, but the 850w would be more effective and would allow for more better graphic card in the future, i believe it has a 3 year warranty.

should last you more then that tho, wait to see what more experianced people say tho befor listning to me saying go for it!

edit : and i think the SLI sticker would have been talking about 2 way sli for gts 450/550/440/540
 
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Stretched said:
i would have personly gone for the 750watt one, but the 850w would be more effective and would allow for more better graphic card in the future, i believe it has a 3 year warranty.

should last you more then that tho, wait to see what more experianced people say tho befor listning to me saying go for it!

edit : and i think the SLI sticker would have been talking about 2 way sli for gts 450/550/440/540
Click to expand...

most likely, ill for out for another 6950 and psu when the 6950 starts to show its age, but ill have to look for the manual for the tx 650 and see :P
 
In terms of PSU I'd mostly talk about noise and how much you care about it.

Most psu's are most efficient at around 50% load, but who cares, a good psu will be say, at 20%/50%/80% load, something like 83/85/83% efficient. So thats not a huge deal, however even the most quiet psu's like the Corsair AX/seasonic(same psu) are pretty noisey above 80% load and can be very loud at 90% load and up so ideally, if you have a quiet rig the more headroom on the psu the better.

A 650W Corsair will be quieter than a 1200W Coolermaster at idle, as in literally quieter but really both below ambient room noise anyway. At 325W the Corsair is probably as loud or louder than the coolermaster and at 600W the coolermaster is likely still essentially silent while the Corsair will be screaming along.

I got a Bequiet psu based on the idea that they rate the sound level at different load levels and have designed them with a low fan speed still at top loads so theoretically is significantly quieter than say a Corsair at max load.

Frankly I regret it on cost, a 1200W coolermaster is cheaper, it would have probably been as quiet at any load level as this psu, but with FAR more overhead should I want to go for say 2x 580gtx's or 2x6990 if I happened to win the lottery :p

Honestly I'd go for a psu by picking things like, brand, go for a half decent brand at the bare minimum, rating, go for something 800W+ so you have safety margin and quiet at low loads, price, frankly I don't see any real benefit of spending £140 on a 750W or £155 on a 850W corsair AX. They are great quality psu's, no doubt but they don't do ANYTHING a psu at almost half the cost can't do in terms of noise, power, overclocking. Then you've got things half way between just above the £110 that can provide over 1000W, will basically end up quieter at any power level, is more than good enough quality and still saves you money.

I do like my psu, but I wouldn't pay £130 for a 750W ever again, total waste, £110-115 would have got me that 1200W coolermaster, yeah its louder at full load, but at 750W draw it would be basically as quiet as the Bequiet PSU so whats the point.
 
I will always stick to my choice of a silverstone st1000p PSU fir £150.
It was less than some 750w PSUs and is exactly the same!!!
It uses seasonic parts iirc and it is very small.
 
roughly...
500W for low spec gaming PC (single £120 GPU low or no CPU / GPU overclock).
650W for mid spec gaming PC (single £200 GPU, med CPU / GPU overclock).
850W for high spec PC (crossfire / SLI £200 GPU med overclock, Single uber GPU high overclock).
1000W+ for monster rigs.

That's probably being conservative as well, but I don't like running PSUs ragged.
 
personally im not one to care about noise lol but i've gotta say, the TX650 is bloody quite :O after i swapped out the stock 230W acer crap and turned it on i honestly thought it wasnt on it was that quite :D but usually i dont hear any noise from my PC, even my 560Ti was silent over my subwoofer, and at 50% my twin frozr was NOISEY :O

i got for the if its noisey, turn up the bass theory... :)
 
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