Will this PSU be sufficient?

[nFeF]

I'm building a new box for my friend, and he want to use this psu he already has in it: http://www.newegg.com/Product/Product.aspx?Item=N82E16817371016

This is what i've got picked out for him: http://pcpartpicker.com/p/RVp4vK

I know it shows 452w on this and technically that's within tolerance but ehh.. seems kind of iffy to me i've never had to deal with that before. I've always just used 700 or 750w PSUs and never worried about it.

What do you think?

 

[TemjinGold]

He'll be fine.

 

[Valantar]

Yep, he'll be totally fine. No reason whatsoever to upgrade to a more powerful PSU. I haven't seen any reviews of that unit, but if there was any reason to switch it out, I'd get a similarly specced 80+ Gold unit, preferably made by Seasonic. Absolutely no reason for more power, even if he plans to OC.

 

[Red Squirrel]

That video card requires at least 750W according to the specs. Video card calculations are odd though since it's not for the card itself but the whole system, but how do they know what mobo/cpu you use, so not sure what kind of buffer they add. It might be assuming that the system has a core i7, while core i5 uses way less power, so you could actually be ok.

I'd get an 850w at least to be safe. Though it would not hurt to try the 550w and check the actual power usage out of the wall. If it's close to or over 550w I'd upgrade the psu as it will stress it too much. Keep in mind what is drawn from the wall is higher than what is drawn from the psu, it's just easier to test at the wall.

 

[TemjinGold]

He will use nowhere near 750. Not even with 2 of them.

 

[BonzaiDuck]

He will use nowhere near 750. Not even with 2 of them.

The adequacy of a 550W PSU is one issue; the remaining use-life of any PSU is another.

The Antec model linked into the OP's OP suggests it is still "young:" It's described as "Haswell-ready." On the down side, Antec product notwithstanding, it only has a 3-year warranty with a price between ~$60 and ~$80. That may be a decent price for a 550W PSU. Put it another way: It isn't a $35 "knock-off."

As to the adequacy of the PSU for a single dGPU/graphics-card -- it is likely more than adequate for that.

For expansion to 2x Xfire (or SLI) cards, It could be a "close fit," and it could be "too close for comfort." It depends.

Over the last several months, I posted threads pertaining to a brand-new 650W Seasonic model with prospects for 2x GTX 970 SLI. There was some mild contention on the sufficiency issue.

I sooner or later determined through my own testing that it was more than adequate. Further, I discovered that rated wattage is based on mean wattage sustainable, and that some good PSUs are able to sustain wattage-draws of 100W+ above the rated value.

The remainder of concerns would arise from over-clocking both the processor and graphics cards in a 2x X-Fire/SLI arrangement. Without any over-clocking, 550W should be amply adequate. Furthermore, if it came "close" in stress-tests, it is then important to observe that such conditions would likely never occur in regular use, and you can then append to that observation the likelihood that good PSUs exceed performance expectations of their spec wattage.

 

[TemjinGold]

We're not talking about 2 cards here with that 550. I'm saying even 2 cards wouldn't use 750 watts.

 

[BonzaiDuck]

We're not talking about 2 cards here with that 550. I'm saying even 2 cards wouldn't use 750 watts.

Personally, if I said 550 was "sufficient" -- I should probably "correct" myself. Depending on which two gfx cards, stressing would likely push beyond that.

In my own case, I'd built the rig with a Seasonic 650, and then chose to add a second GTX 970 -- not initially planned. I took a very close look at it, both measuring and estimating wattage differences. In the very worst case scenario, usage could go to between 590 and 630. If it went 30 to 50W beyond the rated level, I don't think I'd worry about it.

For the 750W and dual gfx, though, I agree. I wouldn't say the surplus is "wasted," but a 650 of good manufacture would do. Further, with CPUs newer than mine and excepting the Haswell E's, I'd actually expect an OC'd system to use less power than mine.