Page 1 of 1

HTPC Airflow - 3 options, 1 build

Posted: Sat Dec 01, 2007 5:04 am
by sikbok
Most of the parts & pieces for my HTPC have been decided on.
However, after the article on the LC17 & GD01, I reconsidered the initial cooling plan.

The important bits for the build, cooling-wise are:
- Case: Silverstone LC16m - 2 80mm rear exhaust fans; optional: 2 92mm HDD bay fans & 1x 80mm side exhaust fan.
- CPU: AMD Athlon X2 BE-2400 - 45W to cool.
- GFX Sparkle SF-PX86GTS256D3-HM Cool-pipe II - Passive (Zalman VNF100) Heatsink on CPU Side; Placed either in 1st or 2nd PCIe slot, depending on clearance.
- PSU Corsair CMPSU-520HXEU - Low noise, intake from outside of case.

That leaves me with the following layout, if I don't add CPU cooling and additional fans (note, al pictures are top down views):

My initial cooling plan involved a top down CPU cooler and filling all the optional fan locations. The cooler I had in mind was the Thermalright SI-128 combined with a Nexus 120mm.
The plan was to see how well this worked and add ducting if either cooling performance of noise was unsatisfactory. As this involves turning the case into a wind tunnel, I reconsidered. Also, the HDD fans would make everything I tight squeeze, perhaps to tight for the CPU Cooling.

The two alternatives I'm considering are:

1) Thermalright Ultima90-based: Simple front to back airflow, with a 90mm fan (see picture below).
- Possibly adding a simple duct from cooler to exhausts, if temps are high.
- Con: Possible lack of GFX cooling?

2) Scythe Minja-based: 92mm fan draws air from GFX over CPU toward side exhaust (see picture below).
- Improved GFX cooling?
- Possibly adding a simple duct from cooler to side exhaust fan.
- Cons: Cooling CPU with preheated air, interferance from rear exhaust?

I'm in need of a reality check, as I see no obvious best solution. So:
- Should I worry about the airflow? Might I be overdoing it?
- What would you do in my situation?
- What have your experiences been with parts like these?

Posted: Sat Dec 01, 2007 10:10 am
by JoeWPgh
If you don't mind a little Micky Mouse engineering, try mounting the PSU 'backwards' with the 120 fan drawing air from inside the case. The reason for drawing outside air through the PSU is to keep it from ramping up under load. If you're not going to be taxing the machine too heavily, this shouldn't be an issue. This lets you 'bury' the fan inside the case, which should be a little quieter and obviously increases your exhaust capacity.

You can Micky Mouse it in with no mods to the case or PSU. You'll find two screws go through the regular case holes, one solidly catches the inside corner of the opening, while the 4rth catches a bit of the case. Unless you're going to use your machine as a football, it's plenty solid enough. If the fan ramping up becomes a problem, it's easy to switch around and you've done no damage to anything.

I'm running a Biostar T690G with a BE-2400 in a LC 17 with a fanless Minja. I don't know if the heat from your GPU would allow this or not, but it's a possibility. My PSU is a Corsair 520HX mounted 'backwards'.

One thing I like about the LC 17 is that with an mATX board, I can mount 3 HDDs in a single cage and then soft mount the cage sideways on a piece of foam and lash it down with some Stretch Magic. I can still hear them if I get close enough, but it quited them down significantly. By the looks of the pictures, the LC 16 doesn't have room for this trick. But a word of warning: Three 3.5 HDDs in a single cage will get very warm, very quickly - especially the OS drive.
I used a 92mm Nexus on the HDD cage and replaced the rear fans with Nexus 80s. All fans are running at 7v. Dropping the fan voltage to 7 raised the temps marginally in normal use. (3 ~ 4c watching/recording SD TV) The difference in idle temps is not even worth mentioning.

Posted: Mon Dec 03, 2007 12:57 pm
by sikbok
Hi JoeWPgH, Thnx for the post : ) >

I think I saw a post here on SPCR that mentioned doing the same thing. Might that have been you?

Think I'll have a go at rotating the PSU. Sound easy to do and to reverse. Noise reduction by putting the fan inside the case is enough reason to have a go.

Ramping-up should not be a problem. The PSU is overkill, so it shouldn't get too hot by itself. I plan to use the same PSU, CPU and possibly Heatsink, so that leaves the 8600GTS and motherboard chipset as additional heat sources.
If those get hot, I'm probably using them to make noise anyway, so revving some fans won't matter too much.

I'm not sure is the PSU trick will help my temps much though, as there will be a TV-card near the intake.
Did your temps drop after the modifaction?

For the HDDs, I plan to do some DIY if they're to noise when mounted in the supplied cage. If I'm correct, I should be able to fit in a 120 nexus and suspend 3x3,5" in the duct behind it. It'll be tight, but it'll be a nice project for during the winter.

Posted: Mon Dec 03, 2007 1:48 pm
by MikeC
Keep in mind that the close proximity of the exhaust fans to the side open vent means the latter will act as an intake -- some of that flow is bound to be evacuated by the back fans without doing any cooling work. The main cooling issue with these cases is inflow.

Posted: Mon Dec 03, 2007 3:53 pm
by JoeWPgh
MikeC wrote:Keep in mind that the close proximity of the exhaust fans to the side open vent means the latter will act as an intake -- some of that flow is bound to be evacuated by the back fans without doing any cooling work. The main cooling issue with these cases is inflow.
I noticed that. I forgot to mention that I slid a piece of cardboard into the 45 degree slot of the Minja to the rear corner of the case. I figured this would direct air from the side vent through the Minja. But I did this at the same time I wired the fans for 7v, so I can't say what specific effect this had.
Next time I go in, I'll pull the cardboard and record the temp differences.

Posted: Mon Dec 03, 2007 5:09 pm
by sikbok
Thnx MikeC. I'll be sure to either use it, or plug it.

Just did a bit more research. The Ultima-90 can only be mounted to blow left to right on the Asus M2N32 Sli Deluxe.

So, from the first post, that leaves the 'left to right' and the 'top down' configurations. I'm starting to dislike the 'top down' option, because it would make ducting hard if the build ends up to hot or to noisy without it.

Based on what both of you wrote on this site, the passive Minja is also sounding tempting.

Posted: Tue Dec 11, 2007 2:58 pm
by sikbok
Just to tie this post up, I've opted for the fanless Ninja Mini option.

I'll be flipping the PSU, both because its quiet and because I can use the airflow in an otherwise neglected part of the case.

If the 2x8 & 1x12 exhausts don't suffice, there's a backup duckting plan targetting both the CPU & 8600GTS.

Posted: Fri Mar 14, 2008 11:39 am
by floepie
Sikbok, which fans and how many of each did you wind up with that made you satisfied with its performance? I'm considering this case for my build, and am just curious what sort of mods/additions I would have to consider to make it ultra-quiet.

PS Were you attempting to install a 120mm fan in place of the 92mm fan at the HDD cage position?