Help with PSU rating

firebird1133 · Feb 6, 2018

So I found this old PSU in a very broken C2Q system that my friend was throwing out, I saw "400w" and friend said it was the only working part so I took it thinking it might be of use. Well a year later and it looks like it could have found a home, I'm building a little gaming PC for my girlfriend out of spare parts I have laying around, (Core i5 750 180 watt max, AMD R9 270x 160 watt max, random Intel Mobo with 4pin power + 12 gigs DDR3 ram, lots of case fans and a mysterious SSD) and Ive got it all except for a PSU. So this sticker on it confuses me handily and I can't figure it out. Just want to see if you guys can decode it and see if it's really 400w and if it can power what I've got.

Any help is appreciated---Phoenix

turkey3_scratch · Feb 6, 2018

It's made by Delta so that's good. Do you know if it has a PCIe cable?

firebird1133 · Feb 6, 2018

turkey3_scratch :

It has 1x PCIe 6pin, 1x CPU 4pin, 1x MOBO 24pin, and a bunch of molex and sata. after some digging it looks to also have a 75% efficiency as well

turkey3_scratch · Feb 7, 2018

firebird1133 :

Efficiency is not a constant thing, it changes based on load and other stuff.

I believe that the R9 270X only needs a six pin, right? If so, then it should be good to use, I don't see why not. Also, your CPU is not 180W, it's about 95W.

firebird1133 · Feb 7, 2018

turkey3_scratch :

Yeah mu version only wants a single 6 pin, I've just hears some stuff about stuff not working because of the psu having the wrong amperage or something. I just put in the load power draw for the processors since they will probably pushed to their limits(she's a PUBG player) so you think it's all good? I was just worried about it since it was that cheap looking gray color with some Chinese text.

turkey3_scratch · Feb 7, 2018

It looks like it came out of a prebuilt computer like a Dell. It has normal power supply dimensions right?

firebird1133 · Feb 7, 2018

turkey3_scratch :

It's normal all around, came out of a prebuilt gaming PC from around 2007 maybe Intex?

turkey3_scratch · Feb 7, 2018

firebird1133 :

Seems it's good to use. If it works it works, you know.

firebird1133 · Feb 7, 2018

turkey3_scratch :

firebird1133 :

Seems it's good to use. If it works it works, you know.

Alright guess I'll give it a whirl, thanks for the help

turkey3_scratch · Feb 7, 2018

The video card recommendation is kind of silly; the actual power consumption of the card is somewhere around like 125W IIRC.

turkey3_scratch · Feb 7, 2018

Corsair's power supply calculator is inaccurate. You can look at reviews of the individual components and see that these calculators are phonies to sell higher wattage power supplies.

Under heavy load his computer should be around 225W.

And the 12V rails sum up to 396W. Not low at all.

And the EVGA 500W likely has worse build quality than a Delta made PSU.

turkey3_scratch · Feb 7, 2018

rayder8989, part of debate is you address points, just saying someone is wrong doesn't actually have any evidence to guarantee such a claim. I'd appreciate it if we discussed matters of power supplies.

turkey3_scratch · Feb 7, 2018

Look at this post by Jonnyguru on Corsair calculators http://www.jonnyguru.com/forums/showpost.php?p=98034&postcount=2 and Jonnyguru is the manager of Corsair for PSUs.

firebird1133 · Feb 7, 2018

rayder8989 :

Yes, I did see that but I've ran GTX 460s in SLI with an 800 watt PSU without issues so idk what to think.

Gam3r01 · Feb 7, 2018

Turkey hit it right on the mark.
Delta makes some great units, and even their low end ones are still decent. If you cant afford a new PSU, use this one for the time being.
PSU calculators are generally quite off (in terms of overestimates). They tend to lean heavy on the high end so people with low quality PSUs that cant actually output their rated wattages are covered.

Gam3r01 · Feb 7, 2018

Yes, 400w is 400w. But the sticker on the side of the unit does not mean its 400w.
Lets say you have a PSU thats rated at 400w, but it has very poor efficiency at operating temperature, and those 400w are spread across multiple 12v, 3.3v, and 5v rails. You really arent going to get 400w out of that unit.

If you have the time and dont mind it, go around and look at the load wattage for each component, its well documented exactly how much those values are. Then plug it into your calculator of choice. I guarantee it wont be near the same.

Gam3r01 · Feb 7, 2018

Then post your findings and references, if you are so certain.
Just saying your numbers are spot on convinces nobody.

turkey3_scratch · Feb 7, 2018

The mathematics works by taking each component of the computer and summing them. If you do this by researching each component, then you will get the actual value rather than the inflated calculator values.

Many power supplies also can run at 100% load for a very long duration of time. For instance, Corsair PSUs are warranty rated based on how long they are expected to last running at 100% load 24/7 under max operating temperatures, and I'm sure other brands follow the same standards.

rayden, since you do not agree with my power calculations, do understand that we both cannot be correct; the power usage of these components is a known thing. I reocmmend you cite non-cslculator sources for your findings because calculators themselves fail to cite their sources. And EVGA, Cooler Master, and Corsair calculators all overexaggerated because they make more money when people buy higher wattage units.

turkey3_scratch · Feb 7, 2018

rayder8989 :

Can you show me your power findings that you have personally done with your own experiments then?

Barty1884 · Feb 7, 2018

@rayder, you're not citing sources (your own testing, or publicly available info), so if anything, I'd suggest others are wasting their own time replying to you* than they are wasting yours.

Delta units, even those provided to OEMs are decent. Branding all OEM units as junk is not any form of "sense", common or otherwise. Doing research on a specific unit or OEM would be the sensible thing to do.

To the actual question, I'd have concerns if this PSU was used for any period of time at any kind of sustained load.
The max output on the dual 12V rails are 300W.....
Given a 180W max GPU (typically 2x6pin), a 95W TDP CPU and the balance of the components, you're right at the 300W max output at load.

Are you sure your GPU variant only requires a 6pin? IIRC, typically they're spec'd at 75W for a 6 pin +75W from the PCIe slot? You can generally do >75W via a 6pin, but most cards >150W use an 8pin....

*Yes, I appreciate the irony in replying to you, wasting my own time.

turkey3_scratch · Feb 7, 2018

rayder8989 :

The discussion of this stuff is relevant to this thread. Please understand, this is a public forum, civil conversation is allowed and you are not required to participate. But I believe if someone is saying something I deem incorrect, I am going to respond to it, just as you will. Understood? I am allowed to talk here just as you are, just as I am allowed to not talk here as you are.

Here is an example of a full system with a 270X https://www.hardocp.com/article/2014/03/10/amd_radeon_r9_270x_270_video_card_review/11

Now many things to note about this system:

-The R9 270X in this one takes two six pins. Power consumption is probably at about 180W-200W for this GPU. OP's 270X he says is single 6-pin, so power must be less. If OP was mistaken then, well, I guess the burden is on OP.
-CPU is an I7-3770K at 4.6Ghz. With the overclock it should have more power than OP's CPU.
-PSU is Antec High Current Pro 1200W, so at this

We can see power from the wall is 372W. At this mark the PSU efficiency should be around 89.5% going by this review. We can therefore use mathematics to determine this to be about 330W. This is when gaming. Once we take into account the higher power consumption of the CPU and, if what he said about his 270X having a single 6-pin, likely lower power consumption of the GPU, I say 300W under load would be a solid estimate. My estimate was low because I was going by memory of the 270X, but now that I did the mathematics it should be between both our estimates. So I do admit my estimate was low. But, this calculation I just performed would still run within the specifications of the power supply.

turkey3_scratch · Feb 7, 2018

Barty1884 :

I did miss that note on the PSU about the combined 12V rails being 300W. But nonetheless, based on my calculations and seemingly your own, it should be just right. Plus OP is using old parts anyway - let's face it, he probably got these things dirt cheap or most of these parts are old. Probably doesn't want to buy a new PSU since something decent costs like $60.

I, too, am wondering if OP was correct about single 6-pin.

CTurbo · Feb 7, 2018

@rayder8989 consider this your one and only warning for language and personal attacks.

It's perfectly acceptable to disagree with somebody on here, but if you cannot present an argument with facts and evidence without resorting to attacking people, you are not going to be here long.

bignastyid · Feb 7, 2018

Honestly I wouldn't use it for the proposed system. The 12v rail maxed out at 300w when it was new, it's an older model and they do degrade over time so it likely can't handle a 300w load anymore. Also by modern standards is more of a 300w PSU than 400w.

A system with a stock i5 750 will use ~ 150w when the cpu is under full load and the gpu idle. The test was done with a GTX 260 which uses 25w in 2d/idle mode so system would be around ~125w .

A stock 270x can use ~177 under load but a heavily oc'd card like the 270x Toxic can use 200w.

So under load you will be close if not over what the PSU is rated to deliver and being an older unit I would not trust it to reliably power the system under that kind of load.

TL;DR It may work but I wouldn't recommend it.

turkey3_scratch · Feb 7, 2018

bignastyid :

Though in a case like this probably another 10-15W from motherboard, case fans, hard drive I'd assume. Was it Prime95 in this test? I'm willing to admit if his power would be too high (admittedly I made a couple of goofs in this thread). I usually like HardOCP's findings which I think would put his 12V rail usage right below 300W so still in spec.

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