nf7-s rev2 mosfet temperature measurements and cooling (11 july 2003)
Temperatures were taken at points L1-L3 (left mosfets) and R1-R3 (right mosfets) during idle and load (left picture). The corresponding points were also measured on the back of the board (middle picture, rotated horizontally). I took the idle temps first, and then the load temps were taken between 20-30 min after prime95 started. The thermistor was placed flat on the mosfet for temperature measurements (right).
After taking the load temperatures, while prime95 was still running, I mounted a 6cm fan (5V), 8cm above the mosfets. After 10 min cooling, I took the mosfet back temperature.
Here're the temperatures, taken at least twice.
|
*Temperature, 0C, idle
|
*Temperature, 0C, load
|
|
| L1 top |
49.3
|
62.0
|
| L1 back |
50.4
|
67.1
|
| L1 back, fan-cooled |
|
57.4
|
|
|
|
|
| L2 top |
48.9
|
68.0
|
| L2 back |
51.4
|
69.1
|
| L2 back, fan-cooled |
|
58.2
|
|
|
|
|
| L3 top |
47.3
|
62.4
|
| L3 back |
47.5
|
63.1
|
| L3 back, fan-cooled |
|
55.1
|
|
|
|
|
| R1 top |
48.5
|
62.4
|
| R1 back |
49.7
|
63.7
|
| R1 back, fan-cooled |
|
53.7
|
|
|
|
|
| R2 top |
45.9
|
63.8
|
| R2 back |
52.0
|
67.2
|
| R2 back, fan-cooled |
|
57.3
|
|
|
|
|
| R3 top |
44.3
|
62.4
|
| R3 back |
51.3
|
65.1
|
| R3 back, fan-cooled |
56.4
|
* tested with a 2100+, 210x11, 1.825V
When cooled with a 6cm fan (perhaps running 10-15cfm), all six mosfets showed reductions in temperatures from the back. Although I've only used fan cooling, I'm convinced that the mosfets can be cooled effectively by mounting heatsinks on top of them and/or with fan.