Heatsink Test – Joe
SUMMARY: Very good performance even at relatively low fan speeds.
The good guys at Thermalright were nice enough to send us a sample of their latest heatpipe heatsink, the SI-128, to test. This model features four large heatpipes cooled by a 120 mm fan.
The base is well finished; I used the Poor Man’s Flatness Test on it with good results:
Parts that ship with the SI-128 include mounting gear for Intel 775 and AMD K8 sockets:
The heatsink for Intel use is mounted to the motherboard using four mounting posts that engage the holes around the socket:
You push down and then rotate the top to lock it in place – the only negative is that in some instances it may require some digital dexterity to reach under the heatsink and do the “push-rotate” sequence.
The SI-128 was tested on an Asus P5WD2 motherboard P4 Motherboard Test Platform with a modified Pentium D 805 to read CPU case temps (both supplied by Directron). The SI-128 was tested with a Delta 120 mm fan at various fan speeds to give a range of results.
| Heatsink | Case Temp | Ambient Temp | C/W | On-Die Temp¹ |
| Thermalright SI-128, 2451 rpm, 56 dBA² | 38.9 | 25.7 | 0.14 | 52 |
| Thermalright SI-128, 1766 rpm, <50 dBA² | 40.7 | 26.5 | 0.15 | 54 |
| Thermalright SI-128, 1028 rpm, <50 dBA² | 46.2 | 27.9 | 0.19 | 59 |
| Thermalright Ultra 120, 2504 rpm | 34.8 | 24.6 | 0.11 | 44 |
¹MBM on-die temperatures.
²50 dBA measured 8″ from the fan intake corresponds to about 30 dBA measured 3 feet from the fan, a very quiet noise level.
Results place Thermalright’s SI-128 in the upper rank of heatsinks tested to date (Heatsink Ranking) with the fan at its highest speed setting. Performance at the lowest fan speed is acceptable; at this setting, the fan is almost silent – inside a case, the fan on low will not be noticeable. I included test results for Thermlaright’s Ultra 120 as a reference point.
Thermalright’s SI-128 is a very good all-around heatsink and a good choice for Intel’s hotties.
Disclosure: Joe Citarella has a financial interest in a company developing thermosyphon products for electronic chip cooling.
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