question about low-profile (horizontal) heatsinks

[schwett]

in a tower style heatsink, the fan or fans blow air to/from the back, top, or front of a case.

the larger low-profile heatsinks have the fan parallel to the motherboard, which means the air is getting blown directly at (and from a very short distance) the side panel of the case. is this really effective?

i'm currently running a corsair h90 in the rosewill mx-2. i don't like the sound the pump makes at idle. debating a custom liquid setup, but rad space is limited and I'm not really sure it would be quieter, given a bigger pump.

clearance from CPU to side panel is about 150mm. not enough for most of the popular tower style coolers.

with the lowest of the low profile coolers, the fan would be about 75 mm (three inches) from the solid side of the case. just seems like a recipe for turbulent, confused airflow and noise. am I missing something!?

 

[WalkingDead]

http://www.tomshardware.com/reviews/low-profile-heat-sink-mini-itx,3639.html

 

[schwett]

thanks for the link. i ended up trying a noctua nh-c14 (fans and sink parallel to mobo) as well as a zalman cnps9900 max, which is about the biggest "tower" cooler that will fit in the case.

i was surprised how well the noctua did given the outer fan being something like an inch from the case side panel. nonetheless, it took both fans running flat out to equal the performance of the zalman with it's single fan. they are both just slightly better than the corsair h90. i don't have a good way to compare noise between the solutions - i'd say the zalman and noctua are both louder than the h90 at full load, but quieter at idle.

the zalman:

the results:

this is from a 3930k, asus rampage iv gene, 32gb ram, evga gforce gtx 770 w/acx cooler, etc. chart is at stock speeds. tried 125 strap and 34 multiplier and temps were still acceptable. will see how far it can go in this case which was clearly not designed for optimal cooling.

 

[aigomorla]

u may want to rotate that heat sink 90 degree's for serveral reasons.

1. you gonna choke the intake due to the clearance of the video card.
2. you will pull warm air from the video card instead of pulling it from the front of your case.

if u have the air sink pulling air from top down, then you will choke at the video card again... meaning u will slam warm air on the video card forcing the warm air to recycle.

 

[schwett]

hmmmmmm. thanks for the input. the intake is at the top though - there a 140mm fan just above the zalman which is blowing air down into it. it is blowing hot air at the video card..... but I'm not sure in this case that it can be helped. that's why I added the two 80mm intakes to the left (back of case), so that all the air isn't going through the CPU sink before getting to the video card or oter components.

 

[coffeejunkee]

I think you need/should reverse all airflow? Use the bottom fans as intake and the top fan as outtake. Maybe experiment with the 80mm fans as in- or outtake, see what gets best results. Possibly reorient the cpu cooler too, from front to back.

Also, low-profile heatsinks are supposed to blow air down onto the motherboard, cooling stuff around the cpu socket too. With sufficient case airflow this shouldn't really be necessary though, and tower coolers will give better results.