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[nextpage title=”Introduction”]

Recently, we published a test where we tried to find out which position of a case fan is the best for CPU temperatures. Now, let’s expand this experiment, comparing the temperatures of the computer “hot spots” under different case fan configurations. Check it out!

In our “Which is the best place to install a case fan? – Part 1” article, we discovered that using an exhaust case fan on the rear or top panel is better than other positions, at least while referring to the CPU temperature.

Today, we will compare the temperature not only for the CPU, but for the GPU (using a discrete video card), motherboard chipset, hard disk drive, and memory modules, with the case fan at different locations: at the rear panel, at the top panel, at the front panel, and at the side panel. We also repeated the test with no case fan at all, with the case’s left panel closed and open, as well as with two fans, one at the rear panel and the other at the front panel, and at the rear and side panels.  We will present the test methodology and results in the following pages.

[nextpage title=”How We Tested”]

We tested different positions for the case fan using a Core i5-2500K, which is a quad-core CPU with a 3.3 GHz clock and a TDP of 95 W. This CPU was overclocked to 4.5 GHz (increasing the multiplier to 45x), with a core voltage (Vcore) of 1.1 V. The video card used was a Point of View GeForce GTX 460 with its stock cooler.

We used a Thermalright True Spirit 120 CPU cooler with the thermal compound that comes with it.

We utilized the Cooler Master Elite 430 case, which has the power supply at the bottom, and has the possibility of installing case fans at the rear, top, front, side and bottom panels. We didn’t test the fan at the bottom panel because the power supply blocked it.

The fan used in the case is the SilverStone FM123. We chose this fan because it is very strong. It was always used at its maximum speed of 2,700 rpm. On tests with two fans, the FM123 was on the rear panel, whereas we installed a Deepcool Wind Blade 120 mm fan (1,300 rpm) at the front or side panels.

We tested the effect of the case fan on the temperatures in different configurations. First, we tested with no case fan and the left panel open. Then we tested with no fan and the case closed. The following tests were done with the case fan at the rear, top, side, and front panels. Finally, we ran a test with one fan at the rear and another one at the front panel, and then one at the rear and another one at the side panel.

Figure 1 shows our system with the rear and front fans installed.

Which is the best place to install a case fan?Figure 1: Test system

Room temperature measurements were taken with a digital thermometer. The core temperature was read with the SpeedFan program (available from the CPU thermal sensors), using an arithmetic average of the core temperature readings. GPU temperature was also measured with SpeedFan.

The temperatures of the chipset, hard disk and memory modules were read using the NZXT SENTRY 2 fan controller, which has five thermometers.

During all of the tests, both CPU and GPU were under full load by running the Prime95 program in the "In-place large FFTs" mode and the [email protected] GPU3 client simultaneously.

Hardware Configuration

Operating System Configuration

  • Windows 7 Home Premium 64-bit SP1
  • NTFS Filesystem

Software Used

Error Margin

Since both room temperature and core temperature readings have 1°C resolution, we adopted a 2°C error margin, meaning temperature differences below 2°C are considered irrelevant.

[nextpage title=”CPU Temperature Tests”]

The following table shows our measurements of the CPU core temperature for each test. The values are in Celsius degrees.

Fan Configuration Room Temp. CPU Temp. Difference
Open case 25 67 42
No fan 25 72 47
Rear fan 25 65 40
Top fan 25 65 40
Front fan 25 67 42
Side fan 25 65 40
Rear + front 25 64 39
Rear + side 25 67 42

The graph below shows the temperature difference between the CPU core temperature and the room temperature in each test.

Which is the best place to install a case fan?

[nextpage title=”GPU Temperature Tests”]

The following table shows our measurements of the video card graphics chip (GPU) temperature for each test. The values are in Celsius degrees.

Fan Configuration Room Temp. GPU temp. Difference
Open case 25 79 54
No fan 25 83 58
Rear fan 25 78 53
Top fan 25 77 52
Front fan 25 76 51
Side fan 25 72 47
Rear + front 25 77 52
Rear + side 25 75 50

The graph below shows the
temperature difference between the GPU temperature and the room temperature in each test.

Which is the best place to install a case fan?

[nextpage title=”Chipset Temperature Tests”]

The following table shows our measurements of the temperature of the motherboard chipset for each test. The values are in Celsius degrees.

Fan Configuration Room Temp. Chipset Temp. Difference
Open case 25 64 39
No fan 25 66 41
Rear fan 25 62 37
Top fan 25 60 35
Front fan 25 56 31
Side fan 25 41 16
Rear + front 25 60 35
Rear + side 25 50 25

The graph below shows the temperature difference between the motherboard chipset temperature and the room temperature in each test.

Which is the best place to install a case fan?

[nextpage title=”Hard Disk Drive Temperature Tests”]

The following table shows our measurements of the hard disk drive temperature for each test. The values are in Celsius degrees.

Fan Configuration Room Temp. HDD Temp. Difference
Open case 25 41 16
No fan 25 44 19
Rear fan 25 39 14
Top fan 25 41 16
Front fan 25 32 7
Side fan 25 35 10
Rear + front 25 32 7
Rear + side 25 39 14

The graph below shows the temperature difference between the temperature of the hard disk drive and the room temperature in each test.

Which is the best place to install a case fan?

[nextpage title=”RAM Temperature Tests”]

The following table shows our measurements of the memory modules temperature for each test. The values are in Celsius degrees.

Fan Configuration Room Temp. Memory Temp. Difference
Open case 25 62 37
No fan 25 66 41
Rear fan 25 60 35
Top fan 25 61 36
Front fan 25 58 33
Side fan 25 57 32
Rear + front 25 60 35
Rear + side 25 57 32

The graph below shows the temperature difference between the temperature of the memory modules and the room temperature in each test.

Which is the best place to install a case fan?

[nextpage title=”Conclusions”]

When we published Part 1 of this comparative, we concluded that the better position for the case fan was at the rear of the top panel. Now, we saw that this can be true for that configuration, but with a hot video card installed, things are a little different.

You can see that the heat generated by the video card affects the CPU temperature, so there were good results with a side fan, but mainly with a two-fan configuration with one fan at the rear panel and the other one at the front panel, which offered the best cooling performance.

The GPU temperature was also improved by a single fan at the side panel. (It was not a surprise, since this fan pushes the air directly on the video card.) The chipset took advantage of the side fan, too.

The hard disk drive, on the other hand, benefits from a fan installed at the front panel (again, not a surprise). The temperature of the memory modules didn’t have a big influence on the case fans.

If we need to make one single conclusion, it should be that using one fan at the rear panel of the case and another one at the front panel can improve your CPU temperature as well as offer good cooling for the other parts of your computer. On the other hand, installing both rear and side fans can improve video card and chipset temperatures at the cost of a little higher CPU temperature.

Please keep in mind that different systems can behave differently because there are a great number of variables involved. That’s why there cannot be only one right answer to the question in the title of this article.