Help with Case Flow Improvement

**diesel604** · 01-25-2003, 07:04 PM

I need some help with case air flow.

I've got a generic 16" ATX Mid tower case which I painted and added a side intake hole a while back. I don't have a camera but I sketched up some diagrams of what it looks like:

http://www3.telus.net/diesel604/diesel604/Mycase1.jpg
http://www3.telus.net/diesel604/diesel604/Mycase3.jpg
http://www3.telus.net/diesel604/diesel604/Caseflow.jpg

I was thinkin of enlarging the side panel hole and install a 120mm fan. Even the 80mm's are geting noisy! But I'm not sure if its worth it to make a blowhole on top as well?

My main concern is to cool the motherboar. My temp readings were 38ºC

when I was running Sandra 2003 burn-in!

I opened up the panel and touched the CPU HSF Hot (which is a good sign since it's transferring the heat) and then the Northbridge heatsink...quite hot!

I have a feeling the MSI KT3 Ultra2 board has the Mobo sensor close to the NB heatsink. Can anyone else confirm this? Anyway here are the Q's

1. Would I benefit if I install a NB Heatsink fan?
2. Should I just have more air flow onto the M/B to bring temps down?
3. How hot is too hot for M/B temp?

**Bovon** · 01-25-2003, 08:13 PM

1. Would I benefit if I install a NB Heatsink fan?
2. Should I just have more air flow onto the M/B to bring temps down?
3. How hot is too hot for M/B temp?

#1) yes
#2) Thats a begining
#3) 5 or more degrees over normal room temps...ie...less than 80 degrees F.

Case temps should be close to ambient temps..no more than 5 degrees F above ambient...if that much.

I believe I would put a 120 mm fan on the case side, opposite the northbridge..this way, you would be delivering ambient airflow onto the northbridge and cpui heatsink as well. You will nee as much airflow out of the case as you have coming in, so an 80 mm on the top would do a good job. You can get fairly quiet 120 mm fans that move lotsa air.

Remember, if you cannot keep the inside of the case fairly cool, you will never cool the cpu because all you are doing is recirculating hot air over the cpu heatsink.

The north bridge really needs a fan attached to its heatsink..if it does not have one...they do get hot...and they do burn out, especially if there is a lot of ram installed. Motherboard makers didn't put fans on the northbridge heatsinks at first...but I believe all of the better makers have gone to doing that now.

If you have a high speed fan on your cpu cooler...see if maybe you can raise it up off of the fins a little...maybe 1/4th inch. If there is back pressure on the fan blades, this will cure that, and increase airflow over the fins.

**diesel604** · 01-25-2003, 08:37 PM

Bovon,

Thanks for the advice! I think I will look for a NB fan and convert the side panel intake fan to a 120mm fan.

Good sketches...what application do you use to draw those.

BTW: As for the sketches I used MS Excel to draw them

Time to go to Canadian Tire to get a Hole saw!

-=[D]=-iesel

**chubtub** · 01-25-2003, 09:09 PM

Careful if you are going to put a 120 on the side. Make sure that the side metal is strong enough to carry it with out much vibration.

I have a fan in the top that seems to help very well to move the hot air out. However wether a top fan works depends on who you ask.

I would be a tad concerned if the HS is that hot. Yes it does mean that your heat sink is working but it may mean that your fan cannot cool it fast enough, or you need a better HS/Fan set up.

**Giblet Plus!** · 01-27-2003, 05:34 PM

I wouldn't be concerned that the V77L is hot. Mine is too, and my load temps are 40C.

If you want even better cooling, you could replace the 70 x 15 mm fan on the V77L with a medium or high speed 80mm fan.

In regards to the blowholes, I would recommend putting them where they can cool the graphics card and processor/northbridge area. Make sure you balance the flow in with the flow out.

**diesel604** · 01-27-2003, 09:43 PM

UPDATE!

I found out that the MoBo Temp sensor for the MSI KT3 Ultra2 boards is located between the AGP slot and the first PCI slot (not near the NB as previously thought).

Ackk I wish I'd read this before installing a NB HSF...well at least its better than just a standard HS

Now the question is if this is indicating AGP/Video card temps....how hot is too hot for an AGP Slot/Video Card?

(My reading is 38/39ºC)

**diesel604** · 01-27-2003, 09:56 PM

LOL *bangs head on desk* I'm such a doofus :X

After I wrote that, I slipped off the side panel

(forgot to mention I temporarily parked a 120mm Sunon fan in the lower left corner facing my PCI slots.)

I had the case panel on (hadn't drilled the 120mm hole yet) during testing.

I took the panel off and whabam....it dropped like a tonnabrix!

I think that solved it (hopefully!)

**Giblet Plus!** · 01-28-2003, 01:11 AM

Drill that hole!

**fizur2002** · 01-28-2003, 01:45 AM

I just moded a 2 foot steel aluminum tower to have a 80mm blow hole on the top and 1 120mm fan on the side panel. The side panel is stiff as a ****ing guard rail, which it could probably handle another 120mm fan on the upper part of it as well, if i wanted it too. Air holes make all the difference my friend.

**diesel604** · 01-28-2003, 02:33 AM

Thanks for all the help guys,

I will modify the side case panel to mount the 120mm Fan and hole (Man thas a big gaping hole!

). Brought the Mobo sensor temp down 10ºC

and it's quieter than the TI-V77L I have on my CPU! I used a Zalman Fanmate to be able to adjust the CPU HSF (Low 2800RPM, High 5200RPM) very handy device to quieten your HSF.

If you want even better cooling, you could replace the 70 x 15 mm fan on the V77L with a medium or high speed 80mm fan.

Hey Giblet....any suggestions for mounting an 80mm to Heatsink? I know 80 to 70mm adapters are rare.

Here are the results of my experiments (see attachment)

Note: CPU Temp I offset +5ºC (to match PC Alrt4) but after reading the OC FOrums for this M/B they said the BIOS reading was more accurate.

**paul0660** · 01-28-2003, 11:23 AM

if the top of your case gets warm a top blow hole is the solution. A side fan that blows onto the graphics card/hsf/chipset area helps, but getting that heat out is the main thing.

**OpK Chowdy** · 01-28-2003, 12:29 PM

my case has a temp between 35-39C based on the time of day. It's **** hot in there. In that case i have 2 intake fans (80mm), 1 exaust bayfan, and that fan in the PSU which really doesn't count. Anyway, my case temps are still high...i was thinking of getting a new case anyway because this one is pretty battered.

Note: right now my case is at 35C, and my processor is at 40C (tbird 1.4ghz)

**paul0660** · 01-28-2003, 12:55 PM

HOt air rises, and it cant get out. Figure out how to vent the case near the top, or buy one that does. I have a 120 or 80 mm fan in the top of every comp i build, as close to directly above the cpu as possible, and mb temps are darn close to room temp all the time.

**chubtub** · 01-28-2003, 01:05 PM

I am with paul0660 on this one. If I turn off my top fan and side fans(2) for about ten minutes (Three fans still going) then turn them on for the first couple minutes I get nice warm air coming out the top then it cools down to room temp.

I can lower my case temp by up to 5c with two side fans and one top fan running.

With full load in the winter 20c in my room I can stay around 34-36c CPU.

**dragflameson** · 01-28-2003, 01:09 PM

Put a PCI Slot fan up against your video card. They are cheap and it will suck a good amount of warm air right off of it and out the back!

I use the Nexus Fan Controller to control fan speeds. Crank all case fans up while using it, turn em all down when it's time to go to bed.

I can easily keep my case temps under control with this fan controller and get it cooler when it needs to be

Drag

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Good sketches...what application do you use to draw those.

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