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Best airflow for my case?

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May 17, 2012 8:21:11 PM

Hi there, I bought a Zalman Z11 Plus midtower case, and it came with a few fans. One on the window-side that cools the harddrive bay (80mm), one on the opposite side planel that cools the mobo since I don't have an SSD (80mm), and one on the rear for exhaust. My PSU does not affect the airflow of the case as it is bottom mounted. I have two 140mm bitfenix spectre pro fans as exhaust on the top, two blue led Zalman fans 120mm on the heatsink (hyper 212 plus), one pushes towards the other, while the one closest to the rear fan pulls hot air from the heatsink into the rear fan. Really complicated to explain. I have a 120mm Antec tricool at lowest setting intaking air from the bottom, and another intake from the front-bottom of the case.

Basically, I'd like to reverse every fan so that I have two 140mm intake on top, one 120mm intake in the rear, one 120mm exhaust on the bottom and one 120mm exhaust on the front-bottom. The heatsink fan closest to the rear intake fan would push air toward the heatsink, while the second 120mm fan would exhaust towards the CD Drive.

I'd essentially have 3 intake, with the two 140mm pushing air in the direction of my GTX 570. My CPU would be getting fresh intake air instead of warm case air, and I'd have two 120mm bottom exhaust fans.

Don't worry about the two 80mm fans, those I can't change. Thank you if you read this far!!!

More about : airflow case

a b K Overclocking
May 17, 2012 9:00:56 PM

Don't be afraid to try whatever makes sense to you. Generally the Intake and the Exhaust must be within 10% of each other. Personally I don't care whether I have a slight positive pressure or a slight negative pressure inside the case.

The thumb rule is: Intake - Front, Side, Bottom --- Exhaust - Rear, Top

The trick is to try various combinations until you get the lowest CPU temp as well as the lowest case temp.
May 17, 2012 10:20:29 PM

Thanks for the reply. I figure as it stands now, my graphics card is running at 40 degrees Celsius, and my cpu at 24 degrees Celsius. Now, I figure the cpu temps won't change if I switch the intake/exhaust because those fans will remain the same. It's the graphics card that will be hit by two 140mm fans instead of one 120mm fan that's partially blocked by the PSU wires that are tied behind the motherboard. The PSU wires must cross the fan before entering a cable management hole.

Meh, I'll try it anyways and report back within the next few days. I got a stable overclock of 4.5GHz with my i5 2500k this morning, ran Prime 95 for around an hour and a half and it succeeded a 16K test. The voltage is at 1.32V. Max load it is at 50 degrees Celsius, and at stock temps it is at 24 degrees Celsius. Right now, with stock settings, it sits at 19 degrees Celsius. Not sure about stock settings max load though.

My graphic card is the primary goal, however.
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a b K Overclocking
May 17, 2012 10:27:33 PM

Nice OC and great temps (CPU).

Go ahead with your experimentation with the fans and air flow. Nothing is cast in stone. Someone once said "If you always do what you always did, you will always get what you always got!"

Change things, monitor temps well, and stick with the formula that works for you.
May 18, 2012 10:02:20 PM

Alright, I have the final results. After reversing the airflow of my case. I can promptly say that there were positive and negative effects. My i5 2500k dropped 3 degrees celsius, it's sitting at 16 degrees celsius right now (stock settings). My graphics card was nearly unaffected and is sitting at 41 degrees (stock settings). It is an increase in temperature, however, because it's lowest sitting temp was 38 before the test, and its highest was 40. It's only been about 20 minutes since I first booted up, so I'll report back after I mess around with my exhaust fan speeds.

I'm going to purchase some compressed air and clean out my graphics card. I'm wondering if anyone could tell me anything about cleaning a graphics card with compressed air? Mine's been running for a year without being cleaned, in a very dusty old case (I have a new case now), so it must be affected somehow.
a b K Overclocking
May 18, 2012 10:49:01 PM

16 ºC = 60.8 ºF (meat locker temp) - can you explain how you obtained such a low temp? It appears below ambient.

Regarding using compressed air to blow off dust - make sure you block the fans and prevent them from rotating. Compressed air has the tendency to rev up fans beyond their design RPM limits and thus damage the bearings. In addition to air use a soft brush to wipe off visible areas carefully. Do not dis-assemble anything in the process of cleaning.
May 19, 2012 3:47:36 AM

Apparently, AI Suite II and Speccy are giving me different temps. AI Suite says 16 degrees Celsius, while Speccy says 24 degrees Celsius. Either way, the low temps are probably because of the rear fan pushing air into the first fan on my heatsink, which then pushes air into a second fan that pulls it out of the heatsink. Also, two 140mm fans are blowing straight down on the heatsink.

I might have to reconfigure the fans to blow more air on the PCB of the graphics card. The heat increase goes against my previous theory, so it must be the the heatsink fans are interrupting the flow of the two 140mm fans.
a b K Overclocking
May 19, 2012 11:39:22 AM

What is your ambient temp? Unless you have some sort of refrigeration coils the computer temps cannot be below ambient.

Try downloading and running RealTemp. Verify that TJ Max is set to 100 degs C.

http://www.techpowerup.com/realtemp/
May 19, 2012 8:31:46 PM

My cores are at 71, 64, 72, and 67 to TJ Max. According to RealTemp, the cores temps are at 26, 34, 26, and 31 degrees celsius.

http://i.imgur.com/oenQW.png

As an update to my previous info, my graphics card was sitting at 44 or so, but for some reason, after switching my fans back to normal (except for the rear exhaust fan, it's blowing air into the heatsink), is sitting at 47. I just got compressed air so I'll report back after I clean everything out.
a b K Overclocking
May 19, 2012 9:15:38 PM

The cores temps don't look right to me. Too much variation between the two methods.

In RealTemp, set TJ Max to 100 degrees C. Then note temps readings.
May 19, 2012 10:26:20 PM

http://i.imgur.com/1suMx.png

Ok, TJ Max was originally 98 degrees Celsius, bumped it up to 100. Temps are 28, 35, 25, and 33. Exactly what's unusual about these temps? And how do I find the ambient temp?
a b K Overclocking
May 19, 2012 11:32:21 PM

BranKeye said:
http://i.imgur.com/1suMx.png

Ok, TJ Max was originally 98 degrees Celsius, bumped it up to 100. Temps are 28, 35, 25, and 33. Exactly what's unusual about these temps? And how do I find the ambient temp?

In RealTemp, TJ Max set to 100 degs C is fine.

The ambient temp is the room temp. - just set a thermometer on the room wall away from the computer's exhaust.

As a general rule, the temps of the cores will be 6 to 10 degrees higher than the ambient (room) temp depending on the season (summer, winter).

Let me know the ambient and then the cores temps.
!