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Alpha PAL8150 Athlon64 Heatsink Review
Author: Dennis Garcia
Published: Friday, April 08, 2005
Benchmarks
The Alpha PAL8150 is a hybrid Aluminum and Copper heatsink designed for the Athlon 64 line of processors. This heatsink will accept a variety of cooling fans and requires a lot of clearance when being installed. Here is an overview of the system and testing methodology.
The system as it was tested
Soltek SL-K8TPro-939
Athlon64 3200+ 512KB L2 Cache 939 ADA3200DIK4BI
Alpha PAL8150 /w Sunon KD1208PTBX-6A 56CFM fan
Cooler Master Aquagate Mini
asetek Waterchill Extreme
Stock AMD Heatsink
CPUCool was used to obtain and record system temperature information and a game of Quake 3 provided the processor usage.
Athlon64 3200+ 512KB L2 Cache 939 ADA3200DIK4BI
Alpha PAL8150 /w Sunon KD1208PTBX-6A 56CFM fan
Cooler Master Aquagate Mini
asetek Waterchill Extreme
Stock AMD Heatsink
CPUCool was used to obtain and record system temperature information and a game of Quake 3 provided the processor usage.
Editors note: Even though the Windows XP task manager reported 100% processor usage we could never attain a 100% of the rated heat output as documented by AMD (see below)
when using Quake 3 as a basis for that heat production. Knowing this the game was played until the maximum temperature was attainted and stabilized, or when the round was over.
Other things to consider when judging software induced heat output.
a) Clock throttling by the processor at high temperatures.
b) Normal software isn't designed to produce maximum heat output.
c) Variances of cooling temperature.
d) Variances in CPU load.
e) Inaccuracies in thermal diode readouts.
Of course the list goes on..
My testing methodology is aimed to provide a real world look into this heatsink given the test system provided.
a) Clock throttling by the processor at high temperatures.
b) Normal software isn't designed to produce maximum heat output.
c) Variances of cooling temperature.
d) Variances in CPU load.
e) Inaccuracies in thermal diode readouts.
Of course the list goes on..
My testing methodology is aimed to provide a real world look into this heatsink given the test system provided.
Default
A C/W rating can quickly be calculated using this formula.
C/W = (CPU temp - Ambient temp)/(Variance(%) * CPU Watts)
Allowed variance for this test = 80%
CPU Watts = 67W
0.41 C/W = (46C - 24C)/(.8(67W))
C/W = (CPU temp - Ambient temp)/(Variance(%) * CPU Watts)
Allowed variance for this test = 80%
CPU Watts = 67W
0.41 C/W = (46C - 24C)/(.8(67W))
Overclocked
For this next test the FSB was cranked up to 255Mhz and the test was re-run.
To calculate a new C/W rating for this test we will need to factor in the increased processor
wattage. The formula and constants for this are listed below.
ocC/W = dCPU Watts * (ocMhz / dMhz) * (ocVcore / dVcore)2
ocMhz = 2550
dMhz = 2000
ocVcore = 1.58
dVcore = 1.39
The variance still applies for our C/W calcuation
Allowed variance for this test = 80%
CPU Watts = W
0.34 C/W = (58C - 24C)/(.8(125.6W))
ocC/W = dCPU Watts * (ocMhz / dMhz) * (ocVcore / dVcore)2
ocMhz = 2550
dMhz = 2000
ocVcore = 1.58
dVcore = 1.39
The variance still applies for our C/W calcuation
Allowed variance for this test = 80%
CPU Watts = W
0.34 C/W = (58C - 24C)/(.8(125.6W))
Benchmark Conclusion
The fan we choose for this review is a Sunon. KD1208PTBX-6A. This fan spins at 5500 RPM and moves about 56 CFM of air. Needless to say this fan is quite loud but shows one extreme in the Alphas cooling ability. The benchmarks showed that at stock speed the PAL8150 was only 3 degrees hotter than the Waterchill extreme, this changed to 4 degrees when the system was overclocked. This is pretty impressive for any aircooled solution.
Keep in mind these calculations are provided for demonstration purposes only and may not reflect the actual lab tested C/W rating, but I think I'm close
Keep in mind these calculations are provided for demonstration purposes only and may not reflect the actual lab tested C/W rating, but I think I'm close
