Fanless Power Supply PC Build Guide

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puddnhead
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Re: Fanless Power Supply PC Build Guide

Post by puddnhead » Mon Sep 10, 2012 10:24 am

Very thought provoking article. I'm considering putting a fanless PSU in my P150 (aka Antec Solo White) case, now that the stock Antec Neo HE 430 is finally creating issues for me after so many faithful years.

One thing I'm confused about though is the discussion/picture of the "typical old school ATX top-mounted PSU case" (which for these purposes the P150 would have to be considered as, since it lacks the top vent/port of the Solo II). The airflow picture in particular (the one on page three with the caption "If a fanless PSU like a Seasonic X400 or Kingwin STR-500 is used, then it becomes an intake vent for the exhaust fan on the back panel.") seems to imply that the airflow will be come in through the back (where fanned PSUs exhaust) and then through the bottom of the PSU, becasue your blue "airflow" arrow is drawn through the bottom of the green box, representing the outline of the PSU. But, for the fanless Seasonics, how is this possible? As you describe yourself in the very next section, Seasonic warns you MUST install the PSU in the case with the vented side facing up -- and this means the underside that faces the motherboard cavity is solid metal & would have little-to-no airflow, no? So wouldn't that picture actually have to show the air coming in the back of the case, horizontally through the entire PSU, then curing around 180 degrees & down to travel out through the back? In other words the airflow through the inside of the case would be longer, it would be a U on it's left side, not a backwards C, with the air traveling further to the right in the picture before it loops back (I hope that description is clear, and I didn't just muddy matters by elaborating so much!)

I think this could actually be a better thing than what you describe, if you use a standard ATX top PSU case unmodded (more on that is a second) -- the air entering the back of the PSU will travel through the entire length, instead of immediately being sucked downwards before it can create airflow in the portion of the PSU towards the front of the case. That seems like a better thing to have happen if your PSU is fanless. But I just want to make sure I am understanding what you would do in this situation, that this picture is incorrect, you are not actually advocating mounting the Seasonic fanless PSUs upside down so the airflow can go that way. And, related, if the picture is wrong, and these PSUs are mounted with vents upwards as directed, are you suggesting that the fanless PSUs are safe to put in a case without the top air vent of the Solo II has (e.g, in my P150?).

And as a second question, if I did try to put a fanless in my P150, how critical would it be or not be to mod it to put a vent (some knd of hole cut into the top and screened on the top back to make it function more like a Solo II in that regard? It would allow more venting, shich on the surface seems good, but I still am wodering, maybe it's actually better to have only one completely air path though the PSU, from left to right in the photo, so that all portions get airflow? If you have the vent in the top then less air would come in through the top of the case back panel, and the right side of the PSU would get more airflow than the left?

Perhaps in this regard, the best thing might be to get the Kingwin, not the Seasonic, and cut the vent in the top above the PSU. Because the Kingwin has the solid heatisnk on the top, the airflow through the PSU would still be left to right. But the heatsink on the Kingwin would take advantage of the vent on the top, the vent would allow the heatsink (PSU) to cool by "convection?"

LOL, better stop now for feedback, is any of this musing making sense to anyone?

Potenza
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Re: Fanless Power Supply PC Build Guide

Post by Potenza » Wed Oct 16, 2013 5:56 am

I'd like to add one question. As stated in another thread, I'm in the midst of finding a new PSU. After lots of reading and searching, I've narrowed my options to the Seasonic X-650 and the Seasonic P-460. Here in Belgium they're roughly the same price, the P-460 being slightly cheaper (€5) at the moment and probably the better option. I was on the verge of buying it, when a major question popped into my mind. My case is a Lian Li PC-A05N and I believe a passive PSU would suit this case quite good. The hot air that rises will be taken away by the front outtake fan. Problem is, I don't plan to use this case much longer because I plan to buy a new GPU within months and I definitely want better airflow and cable management. I'm thinking about the Fractal Define R4.

After reading this article, it seems to me that a case like the R4 will benefit more from a semi-passive/active PSU like the X-series because the hot air goes out at the back. Whilest a passive PSU (like the P-460) would only add heat to the case since the front intake-fans are rather far away to deal with the heat. Heat that will affect the GPU and thus affect the overal noise. What are your thoughts about this?

ggumdol
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Location: Scandinavia

Re: Fanless Power Supply PC Build Guide

Post by ggumdol » Wed Oct 16, 2013 9:48 am

Potenza wrote:After reading this article, it seems to me that a case like the R4 will benefit more from a semi-passive/active PSU like the X-series because the hot air goes out at the back. Whilest a passive PSU (like the P-460) would only add heat to the case since the front intake-fans are rather far away to deal with the heat. Heat that will affect the GPU and thus affect the overal noise. What are your thoughts about this?
As discussed in SPCR review of Seasonic Platinum Fanless 520W and the reference to 400W equivalent therein:

http://www.silentpcreview.com/article1313-page4.html

Both of them seem to be very resilient to heat. You don't need to worry about overheating issues unless they are placed very close (~2cm) to high TDP graphics cards (>100W). In my previous rig, I installed Seasonic Platinum Fanless 400W with its ventilation top facing down (as opposed to their suggestion) and did not encounter any problem for 9 months.
Last edited by ggumdol on Wed Oct 16, 2013 10:49 am, edited 1 time in total.

MikeC
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Re: Fanless Power Supply PC Build Guide

Post by MikeC » Wed Oct 16, 2013 10:09 am

puddnhead wrote:As you describe yourself in the very next section, Seasonic warns you MUST install the PSU in the case with the vented side facing up -- and this means the underside that faces the motherboard cavity is solid metal & would have little-to-no airflow, no?
Actually, no. The underside that faces the mobo (the side on which the PCB of the PSU is mounted) has to be solid, BUT the Seasonic (and most other fanless HS reviewed recently) has lots of vent holes all around, including the sides. Air does flow through it from outside the case to the inside regardless of how it's mounted (in most conventional ATX tower cases) if there is an active back panel exhaust fan.

Potenza
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Location: Belgium

Re: Fanless Power Supply PC Build Guide

Post by Potenza » Wed Oct 16, 2013 1:11 pm

@ ggumdol: Thanks for the input mate. I do not doubt the qualities of the Seasonic fanless PSU's, not at all. Every single review highlights the ability to withstand high loads (and temperatures). I'm more worried about the GPU. It seems to me that the a passive PSU would rise the GPU temperature in an a case like the R4, because the heat goes straight up (instead of going outwards).

Or do I overestimate the heat that a P-460 or P-520 would deliver at normal load? Above of that: installing the PSU with the vented side downwards seems a bit risky to me. Or isn't it?

ggumdol
Posts: 154
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Location: Scandinavia

Re: Fanless Power Supply PC Build Guide

Post by ggumdol » Thu Oct 17, 2013 2:24 am

I'm sorry, I was certainly mistaken. Though your mileage might vary depending on the total amount of power consumed in your rig, to which the amount of heat emitted from Seasonic fanless PSU will be approximately proportional, the heat from the PSU will be largely negligible. Just in case you would better buy a platinum-rated PSU (e.g., Seasonic SS-400FL2) rather than a gold-rated one. I haven't ever noticed considerable heat emission around the PSU in my rig since I bought it in the last year.

From another angle, it might be rather unexpectedly beneficial to have the fanless PSU in a chassis like Fractal Define R4. While a PSU "with" a fan will disturb the airflow created by GPU fans (in case they are common blower-type fans), which might lead to slightly higher temperature of GPU, the Seasonic fanless PSU will not counterflow the airflow of the GPU fans.

I dare say it is a needless anxiety.

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