Testing:
Each heatsink will be tested in an open air system, without other fans to obtain the best possible results with the materials on hand. Arctic Alumina thermal compound with be used for all heatsinks and applied as specified on the respective website and allowed to cure for three days. Processor load will be generated by Prime95 and temperature will be measured by the internal diode. Of course, this is not the most accurate way to measure temperature as even the diode has a good range for variance. Both the Alpha 8942T and ThermalRight AX478 will be tested using a 50CFM YS Tech 80mm fan and the Zalman will be using the included 92mm fan estimated at 50CFM. Both the ThermalRight and Zalman’s fans will be blowing air at the heatsink while the Alpha’s fan will be sucking air through the heatsink.
Processor: Intel Pentium 4 1.8A @ 2.4GHz 1.6V
Motherboard: DFI NB76 EA
Memory: 1x256MB OCSystem DDR400, 1×256 GEiL DDR400
Graphics: Leadtek A250 Ti4400
Sound: Sound Blaster Audigy
Hard Drive: Western Digital Special Edition 800JB
Optical Drive: Pioneer 16x Slot DVDROM
As a note, the motherboard used seems to read temperatures higher than others used. So keep in mind that the values maybe higher when compared to other sites. CPU wattage was calculated at 75.2 watts.
Ambient (C) | Load (C) | Delta (C) | C/W | |
| Alpha PAL8942T | 22.8 | 40.9 | 18.1 | 0.241 |
| ThermalRight AX478 | 20.6 | 39.5 | 18.9 | 0.251 |
| Zalman CNPS6500Cu | 23.5 | 45.6 | 22.1 | 0.293 |
Looking at the data, we can see that the Alpha places first, the ThermalRight second, and the Zalman third. But the Alpha and ThermalRight heatsinks are in the margin of error for the internal diode, so a clear winner cannot be pronounced. Nevertheless, we know that they are both top performing heatsinks. My pick would have to be the ThermalRight AX478 not only for its performance, but for the simplicity of installation, for which it receives an editors choice award. Alpha, as expected makes a strong showing, but the mounting mechanism irks me. The Zalman does come in third place but offers excellent performance for the level of noise.
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