Asus M4A78T-E AM3 motherboard

Viewing page 7 of 8 pages. Previous 1 2 3 4 5 6 7 8 Next

BIOS Fan Control

We tested the board's fan control by connecting the CPU cooler's fan to a variable DC fan controller, so we could lower it as necessary, and proceeded to stress the processor using Prime95 and monitored the fan speeds using SpeedFan/PC Probe. A Xigmatek 92mm PWM fan (2800 RPM) was connected to the CPU_FAN header, a Scythe Kama Flow 80mm 3-pin fan (1600 RPM) to the CHA_FAN1 header, and a Nexus 92mm 3-pin fan (1400 RPM) to the CHA_FAN2 header.

Fan Speed Behavior
Q-Fan Setting
Fan Speed
1540 to 2800 RPM
0 to 1610 RPM
450 to 1400 RPM
Trigger Temp.
/ Range
46°C / 14°C
Fan Speed
2190 to 2800 RPM
0 to 1610 RPM
500 to 1400 RPM
Trigger Temp.
/ Range
40°C / 14°C
Fan Speed
2800 RPM
960 to 1610 RPM
980 to 1400 RPM
Trigger Temp.
/ Range
35°C / 6°C

The Silent and Optimal Q-Fan settings were similar, activating at CPU temperatures of 40°C and 46°C respectively, but having the same 14°C range before the fan speeds topped out. The Optimal setting also had a lower minimum CPU speed. The two Chassis fans seem to be tied to the same controller even though the Scythe 80mm fan did not spin to start (it probably has a higher starting voltage). If either of these two options are used, make sure to use fans with low startup voltages.

The Performance setting had the CPU fan spinning at maximum speed right from the beginning. The Chassis fans began to increase in speed when the CPU temperature reached 35°C, and by the time it hit 41°C, they were both at their respective top speeds as well.

If you decide to use the BIOS' fan control and a decent third party heatsink, we recommend using the Silent profile. We ourselves would connect the CPU fan to one of the Chassis fan headers instead, because of the wider speed range offered. The controller for the CPU_FAN header does not lower the speed low enough in our opinion.

SpeedFan Support

For Windows users, SpeedFan is our application of choice for fan control. It can be configured to raise or lower multiple fan speeds to designated limits when any specified temperature threshold is breached.

SpeedFan with correlations entered. Asus PC Probe on the right.

SpeedFan reported the two Chassis Fan speeds, but for some reason registered only a one or two digit number for the CPU Fan speed. Temp1 matched the CPU temperature read-out in Asus Probe, and Temp2 matched "MB" which, through thermal testing we determined to be related to the temperature of the southbridge.

SpeedFan allows for full control of the CPU and Chassis Fan headers. Speed01 controls the CPU fan using PWM, but cannot reduce the speed below 45% or so. Luckily Speed02 varies the output voltage of the same header resulting in full control. Speed03 controls both fans on the Chassis Fan headers. To enable fan control, select the first chip in the Advanced tab of the Configuration menu and set the three PWM modes to "Software Controlled."


Lower cost boards ship with simple heatsinks on the northbridge and southbridge while those targeted at enthusiasts typically have large heatpipe coolers and heatsinks on the voltage regulation modules near the CPU socket. A well-cooled motherboard can deliver better power efficiency and stability. To test the board's cooling for the various chips on the PCB, we conducted a short thermal stress test for 15 minutes, loading both the CPU and GPU while the CPU fan was reduced to 6V. A spot thermometer was used to read the hottest point on various portions of the board.

The southbridge heatsink and the chokes around the CPU socket registered fairly cool at around 50°C, while the hottest point on the VRM heatsink was about 63°C. The northbridge heatsink, despite it's size was the hottest of all at 85°C. This is a bit higher than we are used to seeing but still acceptable given the lack of top-down cooling from the CPU cooler and our open air testing environment. It should run cooler inside a case with properly directed airflow.

Previous 1 2 3 4 5 6 7 8 Next

CPUs|Motherboards - Article Index
Help support this site, buy the Asus M4A78T-E Motherboard from one of our affiliate retailers!