Which 300W PSU for a GTX 1070 system?

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Quartz-1

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According to [H]'s recent article, a GTX 1070 even with an overclocked 4770K uses less than 300W, so why bother with a more powerful PSU?

The question then becomes, "Which 300W PSU should I use or recommend?"

Indeed, as the 254W power draw is measured from the wall and PSU power ratings are for the output of the PSU, not input, a 250W PSU would do. Would even a 200W PSU do if you're not overclocking?
 
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No, a 200W power supply wouldn't work. Some tests show the non-FE cards using over 200W with factory overclocks.
 
Quartz-1 said:
At low wattages there shouldn't be any issues whatsoever with running a quality PSU at 90%.
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Unfortunately there isn't much of a market for "good" power supplies at such low wattages.

Cards that use <150w have been available for years and it hasn't driven the market to make cheap good quality lower power units. For a normal ATX case, there are a shit ton of good units between 500 and 700w. Economies of scale also dictate those units are priced competitively and readily available.
 
If you are looking for the least power used under normal operation for your system, figure that out and get a power supply that has very high efficiency at that load level.

As for running a power supply at near the max wattage, you are going to end up wearing it out faster as it will run hotter than a higher output power supply would at the same output.

You also have to take into account capacitors wearing out faster under higher temperatures as well the reduction in efficiency.

Personally, if I had a system that was going to pull ~250w under full load, I would get at least a good 400-500w PSU. The price difference is going to be almost nothing.

Oh, and if you want to save some cash on a good power supply, you can still get a good Seasonic 650w PSU off of eBay for $35 shipped. I dare you to beat that price for a good power supply of anywhere near the same wattage.

SEASONIC 650W ATX12V V2.31 EPS12V V2.92 ACTIVE FPC F3 PSU POWER SUPPLY SS-650HT
 
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Quartz-1 said:
I disagree: the likes of Dell and HP will lap them up.
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When something on the level of the CX-430 can be sold for under $20, there isn't much room to go lower. At that point assembly costs are probably more than material costs.
 
I always recommend a PSU with 25-40% more wattage than your system would draw, so that your system will continue to function as the PSU degrades over time. In your example, the system drew 254W at the wall. Assuming the PSU used was 80-90% efficient, that means the actual power draw fell between 203-229W. Assuming a worst case of 230W, I'd want a PSU with a minimum of 322W, so a 350W PSU.

SeaSonic makes some quality 350W PSUs and you've had some good recommendations here. The problem then becomes quality and features. As you go below 550W, the quality/features seem to dry up. A high quality SeaSonic 400W will run you more than the two 550W kings today, the EVGA G2-550 and the Corsair RM550x.

Get a SeaSonic 350W if you care about running your system with the lowest acceptable PSU. It will work, and likely for a long time. But if you care about near silent operation, higher efficiency, modular cables, and some other features, look into the better PSUs. Personally, I'd go with one of the two 550W options above, or if money was no object, a SeaSonic 400W fanless.
 
Most of the very few PSUs with less than 400W that are high quality are SFF PSUs that cost more than similar quality 500W-600W PSUs.

If you've got no reason for getting a PSU with less than 400W other than "my build doesn't need that much", just get a good cheap 500W-600W PSU. They won't consume any more power or generate more heat than a 300W PSU at low power draws, assuming quality is similar.
 
What about an hdplex 250w paired with a 300w power brick and some cooling? I have read multiple accounts of it powering an i5 oc and a gtx 970 .
 
Perhaps a corollary to my original question is, "My Dell / HP / whoever PC says it has a 300W PSU inside. Can I be confident that my GTX 1070 will work fine?"
 
Quartz-1 said:
Perhaps a corollary to my original question is, "My Dell / HP / whoever PC says it has a 300W PSU inside. Can I be confident that my GTX 1070 will work fine?"
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See the Power And Temp page of the HardOCP GTX 1070 Review. That particular test system, with a 6700K at 4.7GHz, is pulling 254W from the wall with the GTX 1070 in. Your PC might pull a lot less if it has a really low power CPU, or it might pull a lot more if it has a really inefficient CPU, but we don't know. That 300W PSU might be a old piece of crap that can't even deliver 200W anymore, but we don't know how old it is.

I wouldn't be confident at all without more information.
 
What's the point in cutting it so close and likely paying more to do so? Especially in a standard form factor system.
 
livfree said:
What's the point in cutting it so close and likely paying more to do so? Especially in a standard form factor system.
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Because the likes of Dell and HP often don't sell their PCs as standard form factor systems, and the typical buyer isn't tech-savvy and just wants to know if it will work.
 
Without a overclock a HDPLEX 250 is a really powerful GPU. But there are much higher-Watt PSU's available for the same price. I don't see a reason to go higher than 550W for a single GPU system though.

Modern Dell's SFF's come with 240W Platinum PSU's as an option, but only have PCI-E lane power. One of those would surely power a 1070 with the right adapters.
 
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thesmokingman said:
I don't understand the desire to run the absolute minimum sized psu.
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Because PSUs on the likes of Dell are often custom, so difficult or expensive or both to replace. So if you don't need to replace the PSU you can spend more on the GPU.
 
Quartz-1 said:
Because PSUs on the likes of Dell are often custom, so difficult or expensive or both to replace. So if you don't need to replace the PSU you can spend more on the GPU.
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What? Is this thread not about you asking which psu to get? What's that have to do with not needing to replace an oem psu so you can spend more on a gpu? And I would never go out searching for a 300w psu, that's ridiculously small and limiting unless, unless you had no choice though Dell has switched to standard psu form factor.
 
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