PSU tier list 2.0

[jonnyguru]

And as I said earlier, there are quite a few cases where the psu is top mounted, not on the bottom. This tends to make the psu the primary exhaust unless there's also a exhaust fan below, next to the cpu. So in effect, the psu sees the entire heat output of both cpu and gpu, possibly. Not a fan personally of that design, which was something to think about when Asus revealed its Ryzen cpu build that included a R7 1700x and gtx1070 in an mATX case with a top load psu and a single intake fan.

"Back in the day" when PCs were less efficient, and PSUs weren't very efficient, this was actually part of the "ATX design guide"; that the PSU was part of the ventilation system of the chassis. This is nothing new, nor is it undesirable. The components within a PSU are far more robust than anything else in your PC.

And while correct in stating its upto the user, that's only mostly true. It can depend on the case and the psu itself. I've seen plenty of older case styles where if you used a psu with a switch in back, the case frame would need to be modified since the mounting hole is off center or not large enough. Sometimes it's even a cutout for the power connection. So occasionally there are limitations as to psu orientation.

Now you're just arguing for arguments sake. We're not talking about HP's and eMachines here.

There still remains a considerable amount of ppl, especially on the indo-asian markets that are still using older FX cpus, with older amd cards like the 290 or 290x, so with summer heat, and no ac, where ambients can hit close to, if not over, 40°C on the outside of the case, adding in the cpu/gpu heat output on top of that just makes for a electronic oven. A fan down psu would make a lot of sense there, especially as the number 1 selling psu in those markets is the Corsair CX, which unfortunately isn't a 40°C unit. The old style anyways.

Right. But they're buying 750W PSUs to power 350W rigs. So the fan might be screaming like a banshee, but the PSU is fine well above those temperatures at those loads.

Never crossed my mind about the hybrid/eco being affected by orientation. Is that something that taken into consideration during design planning and settings choice? Or is it just a blanket number assigned, someone deciding 'oh, we'll kick the fan on at 35°C' etc?

That's most of the fanless PSUs have an orientation indicator that informs the user to mount the PSU with the PCB down. A PSU with a Zero-RPM mode fan is pretty much the same thing, but with a "failsafe" of having a fan. You most certainly can mount the PSU with the PCB on the top side and the fan facing down, but that just means the fans going to turn on sooner.

 

[superninja12]

hot hot hot hot guys !!!

http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=529

 

[okcnaline]

hot hot hot hot guys !!!

http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=529

Holy cow are those units good.

 

[Sakkura]

So even if we place the PSU vertically besides a radiator it shouldn't be a problem unless the air blown into it gets hotter than 40-50°C.

I can't picture what you're describing... but.... as long as the PSU isn't intaking thermals greater than what it's rated at (assuming you'd ever need its full load capability), it doesn't matter how the PSU is oriented.

Capacitor lifespan is affected by temperature, so if I can have a lower intake temperature then that's what I'll go for.

 

[jonnyguru]

Capacitor lifespan is affected by temperature, so if I can have a lower intake temperature then that's what I'll go for.

Then look at the capacitors used. Make sure they're all rated at 105°C. A PSU rated at 50°C is going to have all 105°C caps.

Look at some de-rating curve diagrams when you get a chance. You'll see that most components are unaffected by any "higher temperatures" until they reach a threshold, then they start to decline in performance and/or life span very quickly.

Yeah.... If I have a PC that USES 550W and I only have a budget for a 650W PSU and my ambient temperatures are 40°C I would heed a bit of caution with the PSU quality and it's location and position in the chassis and chassis selection may even dictate my choice. But if I only need 550W and I have something like an EVGA P2 850W, Seasonic Prime or a Corsair HX1000, I put that damn PSU right on top of the hot side of the GPU's radiator and not even think twice of it.

 

[superninja12]

''Hello. My name is Oklahoma Wolf. You didn't kill my father. Prepare to review a power supply.''

where do you find staff like these mr guru?

 

[jonnyguru]

''Hello. My name is Oklahoma Wolf. You didn't kill my father. Prepare to review a power supply.''

where do you find staff like these mr guru?

Our forums. 😀

 

[Karadjgne]

Sheesh JG, I could pick your brain for days..
So much little stuff, that's taken for granted or just plain ignored as being unimportant, like orientation of fanless psus so heat rises out the top vents, or over sizing psus based on derating curves. I'll admit bias to that last one, always assumed ppl were buying 750w+ psus because they were from a cheaper brand than the 550w decent psu they only need. But with derating curves, that actually makes tons of sense, especially in the warmer climate areas. Cool. Appreciate the education.

 

[King Dranzer]

So even if we place the PSU vertically besides a radiator it shouldn't be a problem unless the air blown into it gets hotter than 40-50°C.

I can't picture what you're describing... but.... as long as the PSU isn't intaking thermals greater than what it's rated at (assuming you'd ever need its full load capability), it doesn't matter how the PSU is oriented.

Below are two setups. Which one is better and why?

Setup 1:

Setup 2:

 

[jonnyguru]

Either.

 

[King Dranzer]

Either.

PSU intakes air from the fan and blows out from the back. So if I place a radiator besides the PSU fan which is also pumping the air out(Setup 2 above) it should still do fine. Wouldn't the air pulled into PSU becomes insufficient in this case.

 

[jonnyguru]

Your diagram shows the PSU either pulling air in that comes in from around the back where the left rad is and into the PSU or directly in from the rad on the right.

Either the answer is "it doesn't matter", or your drawing is missing a shit ton of elements.

 

[King Dranzer]

Your diagram shows the PSU either pulling air in that comes in from around the back where the left rad is and into the PSU or directly in from the rad on the right.

Either the answer is "it doesn't matter", or your drawing is missing a shit ton of elements.

Bit more detailed pics:

Setup 1:

Setup 2:

The image is of bottom part of a case.

 

[jonnyguru]

They're both horrible designs. Either a radiator is sucking in hot air or the PSU is stealing air from one of the rads.

Both rads should be intake.

 

[goldstone77]

Jonnyguru just to recap what I think your saying. Just pull as much cool air into the case especially through radiators. And you can use the exhaust through the power supply as long as the internal temperatures don't exceed the power supplies nominal thermals, which for a good power supply is 40C(104F)-50C(122F) I"m just sitting here wed morning getting ready to turn the A/C on, and inlet into my case is 82.3F and exhaust(240mm fan on top) is 88.1F. Exhaust from power supply is 92.3F. I'll add a sketch of my design.

 

[turkey3_scratch]

In your 3D Sketch that would be ideal since the PSU is not stealing air from a radiator. Plus that 3D sketch doesn't really go hand in hand with your 2D sketches.

 

[goldstone77]

In your 3D Sketch that would be ideal since the PSU is not stealing air from a radiator. Plus that 3D sketch doesn't really go hand in hand with your 2D sketches.

Yeah, I know it doesn't match the 2D representation from King Dranzer. I used it to show even though it was 82.3 degrees this morning before I turned on the A/C. that the temp raised 10F on my PSU. Outlets from my case was 88.1F if it went through the PSU you would think it might raise 10F, which would be ~98.1F. This would still be within nominal operation of the PSU.


Edit: What I'm trying to say depending on ambient temperature in most situations you shouldn't have much to worry about by way of the PSU drawing in air from the case to exhaust.

 

[King Dranzer]

I am bad at paint

That is how my setup will be. So as you can see 2 x 480mm RADs and the PSU is placed in between. Which RAD should be for air intake and which should be for exhaust.

 

[superninja12]

with all the respect that design is so horrible, I would considering liquid gpu cooling (custom kit or something like a msi sea hawk)

 

[King Dranzer]

with all the respect that design is so horrible, I would considering liquid gpu cooling (custom kit or something like a msi sea hawk)

That is just bottom unit of case with dimensions 270mm(W) x 150mm(H) x 600mm(D). Both Rad+Fan setup consumes 130mm in width so still 140mm remains out of which 90mm allocated to PSU width(vertical mount) still 50mm gap remains which means 25mm on each side.

 

[goldstone77]

I agree with superninja12, and I would try to redesign this case or get a different one. Why 2 480mm rads, becuase 1 would be good enough. I assume the radiators are on the top and bottom? You want to pull air into the case across the radiators! You don't want to use either one as an exhaust! Can you blow air out from the front of the case? That is going to be one hot box! Can you move the PSU to become the exhaust?

 

[King Dranzer]

Lets leave it for now. Will have to run some tests and decide best solution.

 

[goldstone77]

Lets leave it for now. Will have to run some tests and decide best solution.

Just note that if you have one side as the inlet it will have ambient air blowing across it, and the other one will have inside case temperature air blowing across it. As I showed you above the inside of my case it some ~6 warmer. So, they will change the overall temperature of your fluid making it warmer than it would normally be with all outside air being drawn across the radiators.

 

[Karadjgne]

With regards to the rad on fan side of the psu, that absolutely has to be intake. If used as exhaust, soon as that neighboring fan spins up, it'll create enough vacuum to effectively starve the psu of air, which'll drive psu temps through the roof. If tolerances allow, I'd turn that psu sideways, fan toward the bottom, cut a hole, and feed the fan outside air. That'll put psu solid sides towards the rads, both of which can now be used as intakes or exhaust, depending on orientation, without affecting the psu in the slightest.

 

[King Dranzer]

Lets leave it for now. Will have to run some tests and decide best solution.

Just note that if you have one side as the inlet it will have ambient air blowing across it, and the other one will have inside case temperature air blowing across it. As I showed you above the inside of my case it some ~6 warmer. So, they will change the overall temperature of your fluid making it warmer than it would normally be with all outside air being drawn across the radiators.

The case I am designing can support total of 6 rads( 4 x 480mm and 2 x 360mm).But I am sticking with 4 x 480mm setup in which 2 x 480mm Rads go on top and 2 go at bottom. Designing top part was easy. Bottom part is bit complicated as it is cutoff from top area except for 2 thin slot cuts one for PSU cables and one for Tubing. Even if I provide intake from botom of the case I can only allot space for 2 x 120mm fans will it be sufficient for cooling or should I also make small mesh design in division plate to allot 2 more 120mm fans so that it can pull some air from top area.