Low vs High Wattage PSUs

[nicklmg]

NCIX: http://bit.ly/1bd3ZTx

Amazon: http://geni.us/1mi0

 

Giveaway: http://linustechtips.com/main/topic/351542-vortex-pok3r-giveaway-sponsored-by-massdrop/

 

Do you need a 1200 watt power supply to overclock your shiny new or lightly used processor or video card? Or will a tiny 350 watt unit be enough?

 

Edited April 20, 2015 by prolemur
i gotchu nick :)

[EpIcPoNaGe]

YES I've always wondered about this. Thanks Nick!

[Str_Mape]

The change in shirt really threw me off.

[infernap12]

Regarding the 300W power supply, it pulling 375 from the wall sounds totally reasonable to me. once you factor in the 80% inefficiency your left with only 15 watts more inefficiency OR headway.

[EpIcPoNaGe]

FYI, I think you forgot to link the overclocking spreadsheet that Luke mentions.

[Sakkura]

The 300W Silverstone power supply is rated for a 300W DC output, but when delivering the 300W DC output it's rated for, it will be drawing more AC wattage from the wall because it isn't 100% efficient. It's 80 Plus Bronze rated, which means it should be about 82% efficient at full load (at low testing temperatures; at real-world operating temperatures it might be a little less efficient). If you deliver 300W DC output at 82% efficiency, you're pulling 300W/0.82 = 366W from the wall. Without exceeding what the power supply is rated for.

 

Now, most decent power supplies can deliver at least 5-10% more than they're rated for, a little margin for error baked in. So seeing the Silverstone power supply pulling 375W from the wall is not surprising at all. Not even a little bit. It's what I would expect to see, putting enough load on it.

 

Edit: Changed from the 230V ratings to 115V ratings. Derp.

[Battlehorst]

What does "boot" in this charts mean? That the systems are booting, or that they pass the stresstests with no overclocking?

[LeafInTea]

I actually prefer a "Luke's PSU discovery" and real time testing rather than a video that seems like a report.

[Sokar80]

Corsair AX850 is best 

 

I bought AX850 power 2010 when it released it has been many pc system i have and still running nicely

 

+ power supply test gurus hardocp and jonnyguru tested and highly recommended

 

Corsair AX850 is probably the best 850W power supply we have seen to date

load testing results for the Corsair AX850 were overall outstanding

build quality of the Corsair AX850 is simply excellent

The Corsair AX850 is based on the Seasonic X-Series power supplies  is simply best 850W power supply we have seen to date

 

[peanutsrevenge]

Dang it, was hoping this was gonna be a great video to link to idiots wanting 1TW PSUs for £40, but there wasn't even a S**Tastic 650w-1Kw PSU here.

Quality power > excess power, but that critical point didn't seem to feature in the video. 

All too often people spec a cheap 1Kw PSU for their single, maybe dual GPU system, when I call morons and spec a decent 650-850W they can't understand how that's better than 1KW and this video doesn't help with that

Kinda of a weird video, not really keen on it. If the S**tastic wasn't there, fair enough, it's a comparison of decent PSUs and what can be achieved for different power limits (again, no mention of the importance of 12v max power) which would be useful, but the inclusion of the s**tastic confused matter due to its low power output anyway.

 

 

Just my feedback, as I know you guy love it (it was even the tag line "out viewers correct our mistakes" (which made me lol because I know what it actually 'means')). Always room for improvement

[Bsmith]

nice video, pretty learnfull, altough i would like to say this.

 

 

REMOVE THE CENSORBLEEP ON WORDS!!!

i mean, come on it's freaking 2015, 10y olds even know worse words then that and even on tv(atleast here) it doesnt get censored, only in USA so far i know.

[euzen01]

Very interesting.

[Sakkura]

Did you set up the bequiet! DPP10 550W correctly? I hope you know that it's a multi rail PSU. I'm assuming that you only used one single 12V rail for the TitanX whereas you could've used two.

 

You don't have to worry about setting it up correctly, since the connectors are distributed across the rail such that it's not possible to overload a 12V rail (unless you're overloading connectors).

[Anarchyz11]

A video comparing power supplies at equal wattage, but different quality would have been very useful for new builders. 

 

Still an entertaining video.  Glad to see power supplies getting some love!

[Lays]

I don't think I saw you guys mention that in extreme circumstances you could need more than in the video.

If you plan on extreme over-volting and benchmarking, you could very well exceed these PSU recommendations.

[LOST TALE]

Awesome. Videos like these. New stuff on the table, that have a wide amount of concerned users.

 

I might of been over-estimating my 620w HCG. Didn't expect mid and high end wattage to perform so (lowly).

The death of the scrapyard wars PSU was a nice addition. the outro was also one of the best.

[LOST TALE]

I prefer reports by far as they are more time efficient.

[D3LTA9]

My system is right on the edge of needing more wattage. My HX1000 died after many years of faithful service and as I had just dropped a huge amount of money on a whole new rig and water cooling loop I had hoped that an AX860i would be enough for a 4790k and x2 780's as I couldnt afford a ax1200i at the time.

 

Turns out that whilst it is fine for an average OC of all components, it is not when using customs bioses and raised power targets on both GPU's in order to take advantage of the OC headroom water cooling provides. I am pulling up around 860w (sometimes spikes over this) at the wall under gaming conditions and every now and then I will get a crash with demanding games. Also as the video illustrates it ultimately is the limiting factor on my OC as I cant raise power targets enough without crashes to hold the max OC setting I dial in before temps actually become an issue.

[GrimNeo]

I'm good to go with the Titan X sli oc with an 850w psu. I have a cpu that uses less watts than the 5960x.

[nutral]

Wattage is actually not the correct term for talking about power, watt is the unit of power. so for the title it would be low vs high power psus.

 

This stems a bit from the principle that a quantity or a unit is seperated.

you can only use a unit if you talk about a numer, for example i need a 500w psu else you would use the quantity itself, for example how much power do i need?

 

This stems a bit from other quantities, with length it is, its about 10 kilometers that way or how long is my graphics card?

 

As for the power supplies, it should be rated for how much it can deliver, so it should always pull more out of the wall than the rated power. for example a 500w psu at 90% efficiency would pull 500*(1/0.9)=555w.

[Sakkura]

What you're talking about is a single-rail PSU where you can plug everything in however you want but I'm specifically talking about a multi-rail PSU.

 

You can overload a rail. There are two rails for PCIe on this PSU (I own it myself). The ideal way (for overclocking) is to connect the first cable (e.g. 8-pin) with one rail and the second one (e.g. 6-pin) with the other rail. By doing this the graphics card will be able to draw more than 300W without the PSU shutting off since one PCIe rail is rated for 25A (= 300W).

 

No, I'm specifically talking about a multi-rail PSU. Each of the connectors from a power supply is only rated for a certain wattage. For example, a 6-pin PCIe power connector is rated for 75W, an 8-pin PCIe power connector is rated for 150W. So if you have a 12V rail capable of 20A (240W), and all you connect to that 12V rail is an 8-pin PCIe power connector, it cannot be overloaded unless the connector is heavily overloaded as well. If you hook all the 12V rails up that way, you can avoid any issues with individual 12V rails being overloaded depending on what components the user plugs in (unless components break the ATX specification by pulling much more power from a connector than it's rated for).

[Gigamegabyte]

Nice video didn't realize you need that much power to overclock  :angry:

[Razor512]

I would be interested in seeing an experiment on line ripple (within ATX spec), and its effects on overclocking. (and possibly on audio playback)

 

One area where some power supply makers differentiate them self, is with power stability. Some of the high end ones will pile on the ceramic and electrolytic capacitors in order to filter out as much noise as possible, while others will allow some ripple while still being within ATX spec.

 

Does a more expensive unit that only offers better stability, also offer better overclocking, or even audio playback (less line noise), or does the motherboard do enough to filter it all out as long as it is within spec?

[7850OC]

the +12v number (in the psu) is the real number

 

that we all need to know (in any psu we buy)

 

 

and i can easy recommend a S**T-TASTIC psu :lol:

 

if she have 650w

 

 

but this is all me, and my personal thinking in the subject