How's this for a passive HTPC?

Page 2 - Seeking answers? Join the AnandTech community: where nearly half-a-million members share solutions and discuss the latest tech.

mindless1

Diamond Member
Aug 11, 2001
8,750
1,759
136
mindless1 did not want this discussion to turn into a big debate over passive/active cooling and that's fine. Before everyone runs away from here, could I get some guidance on active cooling:
1. How good is my selection of the Noctua NH-9i + Noctua NF-R8 PWM?

Definitely use the thicker fan on that 'sink if there is room for it, though previously I was not talking about a traditional system build but rather building as if the entire thing was passive, then adding a fan for entire case cooling, just to barely move a little air. I do not own that fan nor whichever motherboard you are going to use so i can't predict how quiet it will be, but it should be reasonably quiet if the motherboard has a fan throttling feature.

2. Would I install the case fan for intake or exhaust? Perhaps I need to run T° tests at load?

I have not kept up on what case you are using which can make a difference.
With a PSU that has a fan forced exhaust, normally the most efficient setup that also blocks noise from escaping is to have a fan under or next to it as an exhaust and block all air intakes besides the one in front of the HDD rack.

If instead it is a passive PSU, do not put an exhaust fan right next to is as this pulls the PSU heat into the case. Instead you'd want an intake fan on the opposite corner of the case or for lack of options if the PSU is on the bottom of the case and drive rack up top, then the fan on the bottom front.

3. Do I need to add any special air filter (the case has none)?

Need, no, but it sure is nice to cut down on dust, to open a 2+ year old system and see it shiny like new instead of dusty.

With exhaust fans and modern cases with holes everywhere you should seal up all holes and gaps except on whichever area you deem large enough to place a filter panel on.

It need not be one of those little fan sized screw-on types, in fact I don't recommend those at all in favor of a much larger filter area medium placed between the case front bezel and case wall if there is no other way to accommodate it. Other areas can be blocked with common packing foam to create a channel so practically all intake air goes through the filter, though even if there are a few small leaks, that's a lot better than nothing.

Popular filter mediums include trim to fit panels made for wall A/C units or slide in pleated filters made for central furnace stacks... better filtration than the former but significantly thicker so it will not fit in as many places. Either can be found at larger hardware stores.

I want to emphasize again that I have been referring to extremely low fan RPM, just enough to get the fan to reliably spin up at power on, with that specific fan RPM depending on the fan model and method used to control RPM. For example the same fan controlled by PWM vs resistive or transistor biased throttling, could potentially result in a different minimum RPM setting needed to spin it up.

Fortunately motherboards that adjust fan RPM based on temperature can compensate in that if the fan failing to spin up causes temperature to rise then the fan gets more juice to spin up which can be reduced later once the temperature drops.
 
Last edited:

crashtech

Lifer
Jan 4, 2013
10,695
2,293
146
Because all else being equal, it always does unless the system were operating at sub-zero temperatures where it needed to stay warmer. Take a passive system with each component running at the respective temperatures they reach. Certain components are very sensitive to that heat and their lifespan is directly effected by it even if the temperature does not reach any particular critical threshold, although there comes a point where the temperature is high enough that the lifespan of the system is reduced below the expected or viable use period based on its performance.

Now add a fan to that same formerly passive system. All component temperatures will go down. The hotter components will be cooled more than the cooler ones since there is a higher temperature differential, but it's a cascade effect since the case air temperature is significantly lower as well.

You may get a decent passively cooled system to run for 4 or more years if you spend enough time and money. A decent actively cooled system with the same attention to detail is expected to run over 10 years. Ask me about my 24/7 operation, 15 year old Celeron 500MHz fileserver...

Note that I started out writing "all else being equal". Using a fan(s) is definitely not a substitute for a high quality PSU, motherboard, etc, with good heatsinking where it is needed. They all work together to make for the best rock solid, long term operation.
I am not going to debate this, other than to say that particularly with today's motherboards equipped with solid caps, there is no data to support the assertion that lifetime will be affected in any meaningful way by incrementally warmer temps experienced in a properly implemented passively cooled build. Generally the increase is on the order of 15°C or so. The only data I have seen in this regard involves spinning platters, which actually have a higher rate of failure at low temps AND high temps, doing best in the high 30s-low 40s C.
 

Bobsy

Member
Jan 5, 2010
166
41
101
Hey guys, it's been a while. I promised I would post after I completed my built. I waited a few months, but here I am at last.

I decided to go for an actively cooled PC. Here is what I ended up getting:

Case: Perfect Home Theater Wesena (Streacom) ITX-7 Silver
Mobo: ASRock H81M-ITX (thank you mfenn for the suggestion)
CPU: i3-4130T (35w TDP)
CPU Cooler: Scythe Big Shuriken 2 Rev B
RAM: Crucial Ballistix Sport 4 GB DDR3-1600 PC3-12800
GPU: integrated
Storage: Intel SSD 320 120 GB (taken from my main PC, where I replaced it with a Samsung 840 EVO 250 GB)
PSU: minibox PICOPSU-120-WI-25 12-25v ATX power supply
Power Brick: FSP Group 120W 19V (FSP120-AAB)
Case fan: Nexus PWM Series SP802512H-03PWM 80mm
OS: Win 8.1 Pro

HTPC_02s.jpg


This was only my second built ever, so I worked on it very carefully.

By going with the Big Shuriken instead of the stock cooler, I was forgoing the HDD tray inside the case. You can see here the difference between the height of the two coolers. (You need to not account for the height of the pins of the Intel cooler for a valid comparison).

HTPC_05s.jpg


With this cooler, there is a gap between the top of the cooler and the inside of the case of about 12 mm (½"). Installing a 25 mm thick fan on the Big Shuriken would reduce the intake clearance to 1 mm, which is too little. According to Scythe, you need at least 10 mm. The stock fan is awesome so no need to replace it.

Then I tested the clearance between some RAM (G.Skill Ripjaw) I intended to use and the cooler. You can see on the picture that there is about 1-2 mm of clearance between the two, so it's fine.

HTPC_11s.jpg


HTPC_13s.jpg


Then I tried testing compatibility between the second RAM stick and the picoPSU.

HTPC_17s.jpg


Here, it was a disappointment. The PSU would ultimately fit (I tried it all the way in), but there was a lot of pressure on the components and connectors. I did not like this. I could have used the Ripjaw, but only one stick. All my sticks are 2 GB, so I decided to purchase some "slim" RAM and went for what I mentioned in my list above. That solved the problem.

Then I put all the core components together. Without the HDD support plate, I had to find another spot in the case for the SSD. I found a great spot between the mobo and the case, at the front, right underneath the IR circuit board. The SDD would be very stable in this location.

HTPC_25s.jpg


Unfortunately, in this position, the circuit board for USB ports, on the other side of the SSD, blocks access to the SSD connectors. I ended up placing the SSD sideways, leaving it lose (I will not forget this if/when I move the HTPC). I plan on retroffiting Velcro or double-sided tape at some point to secure it better. There is room on the side opposite the case fan (that would be right along that PCI-E slot.)

Then I experimented a bit with the routing of the PSU power cable inside the case. First, I considered the shortest route to the connector on the rear of the case.

HTPC_31s.jpg


I had to run the cable above the CPU cooler and between the two fans. I did not like that too much, so chose to route it along the other sides.

You can see the end result (inside) here:

HTPC_33s.jpg


When closed, it simply looks like this:

HTPC_34s.jpg


When I turned it on the first time, the noise was incredible. The Nexus fan was so much louder than the fan that comes with the case! The Big Shuriken was also quite noisy. That was BEFORE I used the ASRock fan utility. When I changed the profile to "quiet" and hit "Apply", it was like magic. Total silence. I kid you not, the system is quieter than even the faintest ambiant noise even with my ear 1 inch from the case exhaust. I was so happy!

When watching videos on this thing, the case becomes noticeably warmer to the touch (it's highly conducive), but the fans never speed up. They are programmed to accelerate once the CPU hits 50°C, but they never have so far.

I am extremely happy with the end result. The fan that is included by Perfect Home Theater is very quiet, however it seems to move very little air. It is not PWM so will be useless should the computer get warm. I am glad I replaced it.

Thank you for your help again and so long.
HTPC_02s.jpg
 
Last edited:

VirtualLarry

No Lifer
Aug 25, 2001
56,587
10,225
126
4. I don't have allegiance except a preference for Intel CPUs (due to a lack of knowledge on AMD and remembering they had lousy x86 compatibility in the late 1990s).

Just an aside. Whomever told you that was spreading FUD. I used AMD CPUs, from the 386DX-40, to the 5x86-133, to the K6-2, and never ran into any compatibility problems. I was an assembly-language programmer at the time too.
 

Charlie98

Diamond Member
Nov 6, 2011
6,298
64
91
Nice build... looks like it turned out well. I have the stock Intel cooler on my HTPC's G620, even in LinX testing it only hits 50C (granted, it isn't in a very tight case BUT it doesn't have that pretty Big Suriken either ;) ) so I don't think you will be having any problems.
 

Bobsy

Member
Jan 5, 2010
166
41
101
I picked the Big Shuriken for silence more than anything else. I trust that the stock cooler would have done a great job to keep everything cool, especially since this PC is only used to play movies, music and show pictures.

Point noted regarding the AMD processors. I'll erase that false perception from my long-term memory!
 

Charlie98

Diamond Member
Nov 6, 2011
6,298
64
91
I picked the Big Shuriken for silence more than anything else. I trust that the stock cooler would have done a great job to keep everything cool, especially since this PC is only used to play movies, music and show pictures.

Point noted regarding the AMD processors. I'll erase that false perception from my long-term memory!

If I would have gone with a bigger CPU or if I ever do anything besides pure HTPC duty, the Big Shruiken will be on the grocery list. :biggrin:

I forget... are you streaming from NAS or server, or what are you doing for local storage?
 

Bobsy

Member
Jan 5, 2010
166
41
101
I am streaming from a NAS for now, but may add a 2.5" 320 GB drive that I have lying around... although I am not sure why I would do that.
 

crashtech

Lifer
Jan 4, 2013
10,695
2,293
146
Much of what we watch on our HTPC is at first stored temporarily on it in a directory that is synched to a directory on the NAS. Once it had been viewed, the decision is made either to delete it or move it into the "watched" directory on the NAS. I have a 750GB data drive in the HTPC that has been running around half-full. This is a method that is left over from the days before gigabit Ethernet, but I've just left it in place because it works pretty good and I don't mind some extra redundancy. Lost a couple terabytes of stuff once, but what bothered me most was losing the stuff I hadn't watched yet.
 

aigomorla

CPU, Cases&Cooling Mod PC Gaming Mod Elite Member
Super Moderator
Sep 28, 2005
21,067
3,574
126
:O

i would totally love to play with a FLM-7

FLM-7-Silver-back-in-1200x800.jpg


it has the heat sink integrated...