How I dropped my CPU & Case temps by more than 10 degrees with $7

[propellerhead]

I'm have an Epox 8KHA+ with an Athlon XP1600+. My case has two fans. One in front pushing air into the case. One in the rear pulling air out of the case. The PSU has its own fan pulling air out of the case. The CPU temperature usually hovers around 46-48 degrees Celsius, and the motherboard temperature was around 28-30.

I turned the rear case fan around so it pushes air into the case. Then, I spent $7 on a clothes dryer vent hose and put my geek hat on. The type of hose I bought was made like an accordion so it can stretch out to maybe 10 feet. I cut a 5 inch section off and used a short piece of 2x4 to shape the round duct into square tube. I shaped it into an elbow and placed it so the outside air pulled in by the rear case fan blows directly onto the CPU. It took a few minutes of bending and shaping to get it just right. In fact, I had to throw out the first elbow I made. With the duct in place, the CPU temperatures dropped to 38-39 and the motherboard temperature went to 34-33. The temperatures are closer together so I don't have a hot spot in the middle of a cool case.

In an attempt to quiet the case, I cut out the grills over the case fans. I also removed the grills over the power supply fan and CPU HSF. Not only was this more quiet, it increased the airflow and dropped my CPU temperature down to 33-34, and the motherboard temperature to 32-33.

In the end, I dropped the CPU temperatures by 12-14 degrees and made the overall temperature more uniform, and made the whole thing more quiet without any fancy expensive cooling stuff.

Pics of the duct
Pics of the case fans

 

[dinde]

very very cool. in thinking of doing the same thing with my case. but, i have a 120mm fan on the back. so ill make it cool the nb/sb also )

 

[Sheriff]

Nice going... I drop my Temps in the Winter by putting on a sweater then opening the Window and in the Summer by running my Aircon duct to my case

 

[Bonesdad]

Pretty cool...how did you attach it to the HSF? Or is it just covering it? It's NOT covering the HS right? but is covering the fan on the HS?

I have a side panel fan that I turned to blow in, as it is right over my CPU...got it lowered 2-3 degrees.

Nice job.

 

[propellerhead]

Originally posted by: Bonesdad
Pretty cool...how did you attach it to the HSF? Or is it just covering it? It's NOT covering the HS right? but is covering the fan on the HS?

I have a side panel fan that I turned to blow in, as it is right over my CPU...got it lowered 2-3 degrees.

Nice job.

Thanks.

The duct fits right over the fan. Maybe part of the heatsink, but not much. The duct is like those tin foil baking pans. They are easy to shape. The duct fits over both fans, and that is enough to hold it in place. No fasterners.

 

[justinm]

Very nice, good use of your grey matter

 

[amdskip]

Looks good, kinda got the Dell/HP concept going there. One thing bothers me though, you really should have a grill for that power supply. Even when the computer is off, there is large amounts of power in there even when the power is killed to everything. The fan grills on the power don't really restrict that much at all.

 

[Cerb]

Does the fan duct affect noise at all? I've been thinking about trying just such a thing when I change cases, but with the metal type bought at hardware stores, would be worried most about it rattling.

 

[Pilsnerpete]

Looks really nice! Why don't you put the grills that come with most new fans on the back? That way the cat's tail quits sucking up and blocking airflow! rrrrrrraaaaaaaaaaaaaawwwwrrrrrrrrr!!!!!!!!!!! hehe. Poor kitty.

No, my real question is how did you cut the holes to make em so clean? Probly didn't use tin snips eh?
Also, what are you using for exhaust (besides the psu)? Did you turn the front one around? Got one of those 5.25" drive coolers?

 

[beverage]

how much quieter does cutting out the stamped metal grills on the case make your computer?

 

[Cerb]

how much quieter does cutting out the stamped metal grills on the case make your computer?

I've done a bit of testing on this. With the stamped grills, it quiets them down significantly and increases airflow. With wire grills it just quiets them down, though the same effect can be had with wire grills by spacing them about 3/8" from the fan. Whatever the term is for the turbulence and pressure changes as the blade passes over the metal, this noise is all but removed by replacing the stamped grills. For spacing the wire grills, any old washers will do, and finding appropriate screws at a hardware store is a simple matter.

 

[propellerhead]

RESPONSES TO EVERYONE:

Yea, pretty much what Cerb said. In fact, run a test yourself. Take your vacuum cleaner and hold your fingers over the hose. Notice the change in the noise level with and without your fingers over the intake. Same principle applies here. Just a lesser magnitude.

There are no cats or young kids around my house. I realize the grills are there for safety and I wouldn't cut them out if I had pets or toddlers around the house. Same goes for the wire grills on the power supply. I'm the only one that sticks hands in the computer case and I am fully aware of the absence of protection. Again, I wouldn't recommend this if you have other people digging into your PC, or you tend to forget you have an exposed fan.

I just used wire cutters (diagonal cutter) to cut the case fan grills out. You can't see it in the photo, but there are a few sharp edges. Again, I wasn't too worried about this since I'm the only one who gets close to these fans.

The duct is light enough to hold its place without any fasteners. There's very little vibration in the case to cause rattling. If rattles, a little duct tape should take care of it. (Gee, imagine that... using duct tape for ducts!)

I left the front case fan pushing air into the case. The PSU fan is the only one pulling air out. I wanted the two case fans to draw in cool air and vent everything out via the PSU.

MORE:

Be mindful of the aluminum duct touching exposed contacts on the motherboard.

I really like having only a small difference between the CPU and motherboard temperatures. It seems this is more desirable than having a cool case. This is probably worth a thread of its own.

I was concerned about the rear case fan sucking in the exhaust from the PSU fan, so I just added a deflector to the PSU fan outlet. I cut up a plastic Coke bottle and taped it to the back so it deflected the PSU fan exhaust upwards and away from the rear case fan that sits just below it.

 

[Woodie]

Interesting...I was playing w/ my setup over the weekend, and backed off, because the temps were worse.

My setup:
Intake fan near the front (not against the front wall), angled to push air towards the mobo.
Rear exhaust fan about where the NB is.
PSU has exhaust fan + intake fan on the bottom of the PSU
CPU & NB have HS/F units.
I have an opening in the rear (about 3cm x 8cm) between the ATX connector and the PSU, so I "ducted" it w/ cardboard & plastic, so it went above the CPU fan. CPU temps went from 53-56/7 and hung the PC (power off boot!). I did test this "intake duct", and it was able to blow out a match held at the opening (outside case). The problem appeard to be that the "duct" was bigger than the CPU fan, so was allowing hot air venting from the HS to be sucked back into the duct, thereby heating the air!

I fiddled w/ it, and got it to stay around 55, but that was worse than just closing off the hole, which brought temp down to 52. Since the room temps are around 25c, and the system temp is around 36-48c, I think I have an overall case/airflow problem. Note, the system temps did not seem to change if I left the side cover off. Hmmmm.

I think I'll try the dryer duct...but how do I get it to help the NB--which seems to be more heat sensitive than the rest of the system. BTW, all measurements were with the CPU under a full load (SoB), but not the IGP. Idle CPU temps almost identical, but NB temps drop off somewhat when I'm done w/ CS.

Here's a few ideas I have (for next weekend):
1. Duct w/ dryer or tinfoil, directly fitted to the HS/F units
2. Duct from the intake fan at the front, rather than just relying on the HS/F to suck the air in.
3. Front-Duct the front intake fan, so it can only suck air in from the front rather than allow recirculation.
4. Reverse the rear exhaust fan (120mm) and duct from there to CPU/NB. (A little reluctant to do this)
5. I do have one more 120mm fan, and I suppose I could try and mount it to the front as an intake fan?? I'd rather not (too much work and too much noise!)

Comments, suggestions?

 

[propellerhead]

Woodie:

A long time ago, I threw just about everything on the store shelves at my PC to get the temperatures down. I tried those expansion slot fans, hard drive bay coolers, big case fans, etc. A lot of that stuff just added noise and sucked power and broke in a few months.

Stick with the simple stuff.

EDIT: I don't think anyone can tell you exactly how to drop your temps. Try things out one step at a time.

 

[Bad Dude]

Hello,
I cannot see that too clear but the question I got is that the only active fan on the heatsink cooler is that back fan or is there one back fan and one on the heatsink cooler too?
Thanks.

 

[link26]

i got way too much dust flying around to do this mod.
dust almost clogged my psu fan.

 

[bearauto]

This is such a great idea...propellerhead, did you remove the CPU fan as well? I've noticed that a high-pitched humming is unavoidable with CPU fans, particularly because the CPU fans are so close to the heatsink (directly on top). Removing it would drastically reduce sound, but the heat may increase dramatically.

Also, there is plastic duct hosing available at your local hardware store...I plan on picking some up, considering I'm a bit afraid of electrical surges with the use of an aluminum duct (however, isn't aluminum conduct heat and electricity very poorly?).

 

[propellerhead]

I left the CPU fan where it was. I just removed the wire grill.

 

[Tuff]

The only Drawback I can see is the NOISE that you will have from your computer....I have done what you have done with the vent hose...works great..but..it will only make a limited difference Ambient air will always be the what crushes air cooling. Unfortunately the best way to go is water cooling...though Quite a bit more expensive.

I did go one step further than you did though...I coiled 25 feet of 1/4 in copper pipe(looked like a spring) and placed it at the end of the vent hose...I then ran cool water through it...made a diff of 2 deg C or there abouts.

After all of this..I finally moved onto water cooling.

But hey...you don't know unless you try Also..one other thing to point out...Use CPUIDLE...great product..it will shave 10 deg C off your temps. @idle

Good luck.

Tuff

 

[Tectron]

Here are Ducts at cyberguys


80mm Duct Kit

 

[bearauto]

What do you guys think of this:

DUCTINGMOD by THERMAL TAKE

 

[bearauto]

Originally posted by: Tectron
Here are Ducts at cyberguys


80mm Duct Kit

Wow, propellerhead's concept in a retail package!

 

[bearauto]

Here's another system for you guys to consider:

RACHAL Computer Vent System

 

[jarsoffart]

Originally posted by: bearauto
Here's another system for you guys to consider:

RACHAL Computer Vent System

That doesn't work. I forgot why, but I read it in Silent PC Review forums, but their forums seem to be down at the moment.

 

[propellerhead]

Originally posted by: bearauto

Originally posted by: Tectron
Here are Ducts at cyberguys


80mm Duct Kit

Wow, propellerhead's concept in a retail package!

Hahaha! They even have that deflector piece! But I made mine out of a plastic Coke bottle.