Fractal Design Define R5 airflow (esp. PSU mounting)

[Ken5d]

I'm not sure if this is the correct forum to post this question in; I hope so.

I'm trying to configure my upcoming build. I'm a semi-novice, having built only 3 or 4 systems in the past (and the last one, in my sig, being over 6 years ago). So I'm sorry if this is a basic question.

My system will be a mildly overclocked i7-6700K, initially using only the CPU's built-in GPU (but next year hopefully upgrading to a Pascal-based GPU). It will have 2 SSDs, 2 3TB HDDs, and 1 blu-ray burner. The PSU is way, way too big, but it was a good price and seemed to be efficient at very low loads (Seasonic 660W Platinum). Haven't decided on my cooler yet.

I want to create a positive airflow. I'm thinking of 2 140mm fans in the front for intake, and 1 140mm fan in the rear for exhaust. My main question is, shouldn't the PSU be mounted upside down (i.e., with the fan at the bottom)? It seems mounting it right side up might mess up the air flow a bit, not to mention it would possibly be feeding off hotter exhaust air of the (eventual) GPU.

I'd rather not have it upside down, but it "feels" like it would be potentially be better. Opinions?

And while I'm at it, since I'd be raising the R5 off the floor to ensure a decent air supply for the PSU, would it be a good idea to add another 140mm intake at the bottom, next to the PSU? Or might that be too much inflow? (I'm planning on removing the unused PCIe slot covers to make sure I don't get backflow, or whatever it's called.)

Thanks, Ken

[CA_Steve]

Chances are, the PSU fan won't be spinning with your loads (even with the Pascal GPU). Plus, your case temps really won't rise enough to have any impact on the PSU performance/reliabilty/noise levels. That said, mount it as you wish.

Just having 2 front and 1 rear fan will be good enough for positive pressure. I don't see a benefit in adding a bottom fan for cooling or noise.

[Ken5d]

Great, thanks! I like it -- the simpler, the better.

[Bearmann]

I think that most people mount their bottom mount PSU's with the fan down to pull in fresh air. On this PSU I think it would make the logo and cable connector writing upside down, yet the writing on the back plate (the only part visible on the outside of the case) would be right side up.

[Ken5d]

On this PSU I think it would make the logo and cable connector writing upside down, yet the writing on the back plate (the only part visible on the outside of the case) would be right side up.

I decided to put it in upside down, since it seemed a "free" improvement even if it doesn't actually make a difference. But the writing on the back place is upside down, along with everything else. Not a big deal, though.

Welcome back, SPCR! I was starting to feel withdrawal pains.

[Quinnbeast]

I decided to put it in upside down, since it seemed a "free" improvement even if it doesn't actually make a difference. But the writing on the back place is upside down, along with everything else. Not a big deal, though.

Welcome back, SPCR! I was starting to feel withdrawal pains.

The problem with making 'gut instinct' decisions when it comes to airflow, is that sometimes the opposite is actually true. I couldn't confirm for certain either way, but my own gut feeling would be you may actually get a little more hot air rising around the GPU because the fan/vent from the PSU is now open to the inside of the case (i.e. which won't be magically negated by simply having a fan there). You could also look at it from the point-of-view that you're drawing warm air through the PSU, which could ramp up the fan speed a create a bit more noise during load. It also goes slightly against your idea of positive pressure, since you now technically have two-in-two-out now that the PSU is no longer sectioned off.

TL;DR - Dunno

[Ken5d]

I couldn't confirm for certain either way, but my own gut feeling would be you may actually get a little more hot air rising around the GPU because the fan/vent from the PSU is now open to the inside of the case (i.e. which won't be magically negated by simply having a fan there). You could also look at it from the point-of-view that you're drawing warm air through the PSU, which could ramp up the fan speed a create a bit more noise during load. It also goes slightly against your idea of positive pressure, since you now technically have two-in-two-out now that the PSU is no longer sectioned off.

Unless I'm completely misunderstanding what you wrote (which is always possible), you seem to have it backwards. What I've done now has the PSU's fan oriented so that it draws in air from the bottom vent of the R5. Any hot air should be directed out the rear (which is true whether the PSU is rightside up or upside down). Nor do I understand why the PSU is less sectioned off than in normal orientation.

Can you explain to me what you meant?

[Quinnbeast]

Nope, the confusion is all mine; I misread your first post. When you said it was "upside down", I took that to mean that the fan was pointing up into the case. I wasn't aware that there were many PSUs or cases where the PSU fan point up was the intended orientation.

Ignore me.

[Ken5d]

Nope, the confusion is all mine; I misread your first post. When you said it was "upside down", I took that to mean that the fan was pointing up into the case. I wasn't aware that there were many PSUs or cases where the PSU fan point up was the intended orientation.

Ignore me.

Ha; no way.

And I wasn't aware that some (most?) PSUs are made so the fan pointing down is the intended orientation (despite the fact that that seems to make the most sense to me). Anyway, I feel better now -- thanks!

[Bearmann]

Well, it is confusing unless you state fan up or fan down. Looking at the owner's manual, it states:

For Platinum-400/460/520 Fanless: The power supply unit must be mounted into the computer case with the ventilation top cover facing UP.....

For Platinum-660/760/860/1000/1200: Depending on the type of computer case, correct mounting of the power supply will result with the fan side top cover facing the mainboard. This does not apply to all types of cases.

http://www.seasonicusa.com/images/Broch ... al_NEW.pdf

So what the heck does that mean? It sounds like it's supposed to be mounted sideways

My semi-fanless EVGA 650 P2 says to mount it fan side down unless the bottom ventilation is blocked.

[Ken5d]

Well, it is confusing unless you state fan up or fan down. Looking at the owner's manual, it states:

For Platinum-660/760/860/1000/1200: Depending on the type of computer case, correct mounting of the power supply will result with the fan side top cover facing the mainboard.
So what the heck does that mean? It sounds like it's supposed to be mounted sideways

You're right, Seasonic is being needlessly unclear; it would be far better to use fan up or down as you suggested. In fact, I like your EVGA wording the best; it would have made my original post unnecessary.

But I think "fan side top cover" means "fan", and "facing the mainboard" means "up" (though only in a tower configuration). But the only reason I can think of why that would be necessarily "correct" is that the writing and socket orientation on the PSU would be right side up.

I think I've beaten this poor thing to death, but until I buy a mobo & CPU, all I can do is think about my build.

[Bearmann]

I can't understand why they can give clear instructions on the Platinum 400/460/520 Fanless immediately preceding it, but not on the Platinum-660. It boggles the mind!

[lodestar]

Images of the Seasonic Platinum-660 clearly show that it is designed to be installed fan upwards



Bearing in mind that the P-660 is supposed to be passive up to about 30% of load the fan upwards configuration should be quieter once the fan does turns on. The issue might be where the PSU fan would draw its air from once it is on. Given the large grill on the back panel of the R5 that stretches the length of the PSI expansion slots it could pull air from outside via that grill. This is maybe why a fan might be worth fitting in the bottom position next to the PSU to provide a positive pressure zone of filtered intake air. And it would of course provide the same effect hopefully even when the PSU is operating without the fan being on. Reviews including SPCR's have concluded that this bottom fan position does not seem otherwise to have any great impact on cooling of the CPU and/or GPU. Perhaps this is because of the size of the rear grill on the R5.

[Bearmann]

There may be an advantage of having the fan, and therefore the grill, up when the the unit is in passive mode with the fan off. I would think that this would allow the unit to release the heat more easily and keep the unit cooler.

[Ken5d]

I think that does make sense, so I can understand why they say to mount it right side up.

However, I intend to run the PSU without Fanless Mode, so my understanding is that means the fan will always be spinning, but silently (unless the PSU ramps it up, of course). In which case, mounting it upside down seems the (slightly) preferred way to do it.

If I had all the parts to my system, and the time to play, of course I'd love to actually just try it both ways and measure what difference, if any, it makes. Sadly, I have neither.

[CA_Steve]

If I had all the parts to my system, and the time to play, of course I'd love to actually just try it both ways and measure what difference, if any, it makes. Sadly, I have neither.

..and until you get a high wattage gfx card, it's probably negligible.

[Bearmann]

I emailed EVGA about this (in relation to the Supernova 650 P2 PSU):

I know the owner's manual says to position the unit with the fan down as long as there is adequate ventilation on the bottom of the case. It seems like that in ECO mode it might be better to have the grill in the up position so that heat doesn''t build up within the PSU when the fan is off. Can you shed some more light on this?

Their reply:

Positioning the fan down can minimize dust falling into the power supply. For heat build-up the warm air can still vent out of the back of the power supply. If the temperature does increase to where the fan turns on it would be under load as idle temperatures for an average system in either position would not require the fan to turn on.

Regards,
EVGA

[quest_for_silence]

so that heat doesn''t build up within the PSU when the fan is off

You are over concerned about that: actually there's no harmful heat build up (the EVGA answer sounds rather reasonable/correct).

[Bearmann]

so that heat doesn''t build up within the PSU when the fan is off

You are over concerned about that: actually there's no harmful heat build up (the EVGA answer sounds rather reasonable/correct).

And yet it appears that the Seasonic is designed for the fan to be in the UP position. Maybe a Seasonic owner could send them an email requesting further clarification.

[quest_for_silence]

And yet it appears that the Seasonic is designed for the fan to be in the UP position.

I don't think so.

[Bearmann]

And yet it appears that the Seasonic is designed for the fan to be in the UP position.

I don't think so.

I don't know, but lodestar thinks so. Maybe an email to Seasonic would help clear this up.

[quest_for_silence]

I don't know, but lodestar thinks so.

I often disagree with lodestar.

[Quinnbeast]

The orientation of the PSU should be dictated by the case layout, not by the intention of the PSU manufacturer. If you're using a traditional mATX/ATX case layout (such as a Silverstone TJ08), then having the fan point up with involve it being about 1cm from the solid top panel. If the PSU is in a case with a bottom/rear mounting position and the case has a suitable intake on the bottom panel, then a pointing the fan up into the case would be missing out on a key feature of the case... but not likely the end of the world either.

[lodestar]

Back in 2009 when SPCR reviewed the Seasonic X-650 it was quite clearly intended to be used fan down



whereas today's Seasonic X-750...



but this doesn't prevent a user from fitting a PSU in either orientation provided the case supports it.

[quest_for_silence]

lodestar, do you know those two PSUs are internally almost identical?

[Abula]

The only PSU that do matter the orientations on the Seasonics are the fanless, the rest really dont matter, if the temp threshold is reached the fan will start, it will probably start less facing up since it will let hot air get out, but at the same time that heat is beign released inside the case, thus all other components should have higher temps.

I used a Sesonic X650 for 3 years facing up on TJ08-E, then i moved to a Define R4 and used it mounted fan down, then i bought a Seasonic SS-860XP2 and used it the same way on the R4, now its move to a FT05 and its sideways, and i dont have any problems to report.

[Ken5d]

The only PSU that do matter the orientations on the Seasonics are the fanless, the rest really dont matter, if the temp threshold is reached the fan will start, it will probably start less facing up since it will let hot air get out, but at the same time that heat is beign released inside the case, thus all other components should have higher temps.

That makes a lot of sense to me; it sounds exactly right.

I wrote Seasonic yesterday to ask them, just for fun, but so far I haven't had a reply.

EDIT: It's now been 2 full business days, and part of another, without a reply from Seasonic. That's disappointing; next time I'm in the market for a PSU, I'll give EVGA (Super Flower) more consideration. I don't normally use a PSU's tech support, but it's good to know it's there if needed.

[lodestar]

lodestar, do you know those two PSUs are internally almost identical?

In fact, they are quite different.

The original X-650 and its derivatives had 12V output components which were on the solder side (underneath) of the main circuit board and used the PSU casing as a passive heat sink. Early versions used thermal paste between these components and the casing, later this was changed to a thermal pad. As a consequence if this design of PSU is fitted fan down the top of the casing is hot to the touch, even under idle conditions.

The current X-650 and X-750 (KM3 versions) use a completely revised main circuit board which is based on the one used by the Seasonic Platinum PSUs. The component layout is different. The output components are no longer underneath but moved to an additional daughter board, so the PSU casing is no longer used as a heat sink. A benefit of using the Platinum design of circuit board is the fan control switch to toggle between Hybrid and Normal modes.

[quest_for_silence]

In fact, they are quite different.

You have really no idea about what you said.