Downside to too much PSU?

[increment1]

Is there a downside to over buying and purchasing a PSU with too much wattage? Besides the obvious (price), are there negatives in terms of efficiency and (more importantly) thermal characteristics?

The reason I ask is because I am considering buying a Seasonic X560, however, the X660 is on sale for about the same price. I do not need a 660W power supply, but if it operates better or the same at my typical usage then it seems like a better deal.

Would an X660 run cooler (and/or quieter) than a X560 at the same wattage (say a typical non-SLI, non overclocked PC)?

 

[TemjinGold]

Not really a downside. Difference in power cost is minimal.

 

[increment1]

Thanks!

Happy with your X660?

 

[lehtv]

An overkill PSU will have slightly lower efficiency at idle, but compared to a lower wattage unit, may actually have slightly better load efficiency. In any case, the difference in power costs is minimal, as TemjinGold said; especially true when comparing 560W to 660W. Even if you were comparing 560W to 850W, you wouldn't really need to worry about electricity costs.

 

[TemjinGold]

Yep, my X660 is great!

 

[BFG10K]

The high wattage ones can have larger dimensions which can obstruct case elements (e.g. routing holes, bottom intake fans), but that won’t be an issue for the X-660 as it’s standard size.

Also some have more hard-mounted cables but again, that won’t be an issue with the Seasonic as it’s completely modular.

 

[philipma1957]

Thanks!

Happy with your X660?

my 660 is fine buy it instead of the 550

 

[increment1]

Ok, thanks for all of the advice! I will be getting the X660.

 

[IGemini]

HardOCP's reviews of both basically say they're the same unit, with the exception of the power rating: same construction, efficiency curve, operating temperatures etc.

There's not really any benefit to getting the 660 if you're not OCing or running multiple GPUs. Even with your entire system at 100% load, I don't think the PSU will reach 50% load when it gets most efficient, and may spend a lot of time <20% where the unit is least efficient.

I'm not saying the X-660 is a bad unit at all, but your hardware won't use it well. Unless you have any future prospects for Crossfire, there's no reason to get it just for "moar power."

http://www.anandtech.com/show/5767/capsule-review-sapphires-radeon-hd-7870-overclock-edition/4

 

[aaksheytalwar]

Less use might cause slightly lesser efficiency but it is practically irrelevant in all respects.

 

[lehtv]

There's not really any benefit to getting the 660 if you're not OCing or running multiple GPUs. Even with your entire system at 100% load, I don't think the PSU will reach 50% load when it gets most efficient, and may spend a lot of time <20% where the unit is least efficient.

I'm not saying the X-660 is a bad unit at all, but your hardware won't use it well. Unless you have any future prospects for Crossfire, there's no reason to get it just for "moar power."

However, since the X-660 is on sale for the same price as X-560, there's no harm in getting it. If nothing else, at least it'll have better resale value.

 

[IGemini]

Resale? I'd use a Seasonic until it died. In this scenario, more power = less efficient 100% of the time it'll be used, that's all I'm saying, but whatever.

 

[TemjinGold]

In this case, the difference will be pennies at most. He does get the added benefit of extra room essentially for no extra cost. I'm generally against "lots of headroom" if it costs you way more upfront to get it. But for the same price, why not?

 

[Don Karnage]

I run an AX1200 and my system probably only uses maybe 500w. There is no con to owning a high efficient power supply then using 40% of it's power rating

 

[lehtv]

Resale? I'd use a Seasonic until it died.

Obviously you wouldn't be selling it because quality issues. You'd be selling it either because of insufficient wattage (e.g. you're planning a tri-SLI setup or somesuch), or because of no further need for a midrange gaming PC, or a PC altogether.

 

[georgi984]

so much reply's and no one's mentioning the benefit of having higher wattage Seasonic PSU's.
Special Features -

5. Seasonic Hybrid Silent Fan Control

So if you manage to stay under 20% load it's becoming Fanless psu

 

[lehtv]

Both PSUs have Hybrid Silent Fan Control, which is probably why no one mentioned it

 

[TemjinGold]

I run an AX1200 and my system probably only uses maybe 500w. There is no con to owning a high efficient power supply then using 40% of it's power rating

If it's the rig in your sig, it uses nowhere near 500w (more like half that.) The con is you spent 4-5x the amount a right-sized PSU would've cost you. Not judging, just pointing that out.

 

[aaksheytalwar]

I run an AX1200 and my system probably only uses maybe 500w. There is no con to owning a high efficient power supply then using 40% of it's power rating

This, same here, look In sig

 

[IGemini]

If it's the rig in your sig, it uses nowhere near 500w (more like half that.) The con is you spent 4-5x the amount a right-sized PSU would've cost you. Not judging, just pointing that out.

Fundamentally nothing different than what I'm pointing out. I'm not saying using the power supply @ 40% is bad, but at 10-15% isn't doing any favors. I'm using idle loads because most computers spend the majority of their time there.

Here's my logic: The AT link I posted likely uses more power than the OP's machine (assuming we're talking about the same hardware from other posts @ stock instead of the OCed testbed), and that's using a Quattro 1200W. That test system would probably idle at 85W or so instead of 105W if it wasn't overpowered because efficiency drops quite a bit below 20% load. It makes the unit work harder to supply less power, and not unreasonable to assume it might be warmer as a result--I can't be sure there. But even with a 20W difference, any "cost saving" by getting the X-660 at the same price would be burned after a year of constant idle time (assuming 15c/kWh). That's before I factor in either PSU choice in this thread. The X-560 would be a better fit for that computer's power envelope because it won't work as hard.

If the OP has plans for Crossfire/SLI/OCing, go for the 660.

 

[TemjinGold]

Fundamentally nothing different than what I'm pointing out. I'm not saying using the power supply @ 40% is bad, but at 10-15% isn't doing any favors. I'm using idle loads because most computers spend the majority of their time there.

Here's my logic: The AT link I posted likely uses more power than the OP's machine (assuming we're talking about the same hardware from other posts @ stock instead of the OCed testbed), and that's using a Quattro 1200W. That test system would probably idle at 85W or so instead of 105W if it wasn't overpowered because efficiency drops quite a bit below 20% load. It makes the unit work harder to supply less power, and not unreasonable to assume it might be warmer as a result--I can't be sure there. But even with a 20W difference, any "cost saving" by getting the X-660 at the same price would be burned after a year of constant idle time (assuming 15c/kWh). That's before I factor in either PSU choice in this thread. The X-560 would be a better fit for that computer's power envelope because it won't work as hard.

If the OP has plans for Crossfire/SLI/OCing, go for the 660.

You would be correct except the Seasonic X-series does not drop off nearly as much as you think. At idle, it certainly will NOT be 20 watts of difference (more like 2). As I said, the difference will likely be pennies a month between the two and since the unit isn't going to cost more (the primary cost issue), the OP is getting more headroom for next to no extra cost. This is very different from the 2 guys on this thread who bought monster PSUs for WAY more upfront cost than a right-sized PSU and are using <10% load at idle. Once again, the major expenditure waste there is the initial purchase price. The difference in energy cost there will be noticeable but still fairly negligible.