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I recently purchased the Fractal R2 Mini (Great case BTW and highly recommended) and the H80i. I was undecided about which way to direct the fans across the radiator so i conducted testing in both ways and was surprised by the results. Prime 95 and Heaven Benchmark were ran for 15 mins each. Temperatures were measured at the end of each test. Test area temperature outside the case was 22 C. Corsair Link software was used for temperature verification as well as MSI Afterburner. Custom fan curve was used in Afterburner. Balanced mode was used in the Corsair software thus the fans were spinning at around 1400 RPM. System was booted up both times and allowed to idle for 20 minutes before test. GPU was running at stock speeds of 925/1250. Power boost was set to 20% + in Afterburner to prevent the core from fluctuating. Arctic MX-4 was used on the H80i using the dot method. Interior case temps were taken in Fahrenheit and converted to Celsius. All case fans were running in 12 v mode.

Custom Fan Curve in MSI Afterburner:



Test Bed:

Motherboard: GIgabyte Z97MX Gaming 5

CPU: Intel [email protected] 4.0ghz (1.121 v)

Power Supply: XFX 550w

Video Card: Power Color 7950 Boost+ (925 mhz core, custom style cooler, does not exhaust out of the case)

Memory: PNY 8GB x 1 DDR3 1600

Hard drive: Samsung 850 Evo 250 gb

Case: Fractal R2 Mini. (Fan placement as follows: 2 x 140 mm in the top in exhaust, 2 x 120 mm in the front as intake)

Corsair H80i

Programs used in test:

Heaven Benchmark 4.0

Prime 95 v 28.5 in blend mode.

The circled area in the picture below was were the temperature was taken from. Notice how close it is to the GPU and it's placement is right in front of 2 x 120 mm intake fans.



Test 1: Fans in intake configuration:

Interior case temperature at start of test: 23.88 C.

Heaven Benchmark GPU max temp: 64 C.

CPU average temp during Heaven Benchmark: 46 C.

Interior case temperature at completion of Heaven Benchmark: 28.8 C.

Interior case temperature at start of Prime 95: 28.8 C.

Interior case temperature at completion of Prime 95: 26.6 C.

CPU max temp during Prime 95: 62 C.

Test 2: Fans in exhaust configuration:

Interior case temperature at start of test: 24.16 C.

Heaven Benchmark GPU max temp: 56 C.

CPU average temp during Heaven Benchmark: 44 C.

Interior case temperature at completion of Heaven Benchmark: 23.8 C.

Interior case temperature at start of Prime 95: 23.8 C.

Interior case temperature at completion of Prime 95: 23.8 C.

CPU max temp during Prime 95: 58 C.

I was shocked by the results. Not only did the CPU obtain better results in exhaust, but EVERYTHING inside the case was much cooler. I didn't record the thermal sensors on the motherboard but i remember them being considerably lower in exhaust mode. My theory for why exhaust is so much cooler is pretty simple. Heat rises but if enough heat builds at the top, it has no where to go but start going down. The 2 x 140 mm fans at the top simply could not keep up with the heat load being produced in intake configuration. My guess is if you have a reference style cooler and your GPU heat can be exhausted out the back, temperatures may be slightly better in intake configuration. However, i still think overall that the intake configuration will fair worst than exhaust if the back of your case is close to a wall (my case is 4 inches/101.6 mm from the wall). The reason behind this is all the heat is exhausted out the back of your case by your PSU and GPU. The heat will rise and be pulled in by the Corsair fans in intake mode. Not everyone's configuration will be this way but for majority of PC builders these principles will apply. Below are some pics of my finished build. Hope this can save some one the trouble of figuring out which way is best if they have a similar configuration.


 

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When you run prime 95 to heat up the CPU, everything else being idle, your temps exhaust vs intake would be about the same. If you're pulling air from within the case to cool the CPU, and nothing is warming that air, you won't see any negative side effects.

To see the benefits of the CPU radiator as intake, you would need to be running your GPU at the same time as the CPU... Like you would while gaming. In that scenario, you would notice much larger benefit of having your CPU radiator getting fresh air outside the case. Imagine if you had two r9 290s in the case running full tilt. You wouldn't want the hot air from those graphics cards feeding your CPU radiator.

You did some nice testing. I would be interested to see the CPU results when the GPU is at full throttle. Run prime95 and heaven together, or if that's too strenuous, run a game benchmark on loop for a while to warm the CPU and GPU simultaneously.

Nice thread. Lots of people ask this very question a lot.

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This is true to a point but you need to remember that even tho my CPU was not maxed out during Heaven, it was still being utilized at around 60%~70% if I remember correctly. Playing a demanding game that maxes out both CPU and GPU would result in higher temps overall in the case, but Im sure the overall end results would be the same. Thank you for the rep.
 

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Cases with excellent air flow, using the CPU radiator as exhaust is just fine. This was the configuration I used. The other way around, you are pumping hot air from your CPU into the case, which isn't ideal either. On the other hand, if you had multiple GPUs cranking out the heat, then having the CPU radiator in taking outside air is more ideal. People need to do essentially what you did, which is try it both ways and run some quick tests. No one config fits all.

Good work again. I really enjoy cooling configuration threads. I think cooling and air flow setups might be one of the most over looked aspects by amateurs. It's also the most debated, but I won't get into that. Just don't ask people what the best fan is
smile.gif
 

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Quote:
Originally Posted by Depauville Kid View Post

Cases with excellent air flow, using the CPU radiator as exhaust is just fine. This was the configuration I used. The other way around, you are pumping hot air from your CPU into the case, which isn't ideal either. On the other hand, if you had multiple GPUs cranking out the heat, then having the CPU radiator in taking outside air is more ideal. People need to do essentially what you did, which is try it both ways and run some quick tests. No one config fits all.

Good work again. I really enjoy cooling configuration threads. I think cooling and air flow setups might be one of the most over looked aspects by amateurs. It's also the most debated, but I won't get into that. Just don't ask people what the best fan is
smile.gif
You are right about the multiple gpu's, if they are custom style coolers the heat would be a ton. Looking at my pictures has me thinking about other configs, like reverse one of the top 140mm closest to the radiator or moving one of the 120mm fans from the front to the bottom under the gpu. That's just one of the great things about this case. For an mATX case, it's got so much adjustability to it.
 
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