Branded by former experience with the Pentium 4 3.6 GHz (throttling under load due to overheating) and Athlon 1200 processors (product killed in action when fan was removed), we decided to put AMD and Intel low-cost and high-end processors to a special stress test by disconnecting the processor fan in order to simulate a fan failure. Although all the processors except the high-end Athlon 64 X2 are based on the latest manufacturing processes, most products still heavily depend on a proper cooling solution when taking on workloads. Even so, we also want to mention that all four configurations were workable and reliable without a working fan when running idle. Clearly, both AMD and Intel did a great job in reducing power requirements when the processors don't do anything.
Removing the CPU fan connector cable is a really simple way of simulating a processor fan failure. It is interesting to draw some conclusions from our test:
- The AMD Athlon 64 X2 6000+ (125-W model) did not complete any of our benchmark runs once the CPU fan was disconnected. It clearly dissipated so much heat that either the motherboard or the CPU initiated a system shutdown after only a few minutes.
- AMD's Athlon X2 BE-2350 has the greatest potential to withstand a failed CPU fan, as it is rated at a maximum power requirement of just 45 W. This, however, didn't really help much, as the test system using the Athlon X2 BE-2350 only completed two out of ten benchmark runs. Again, the system shut off after a few minutes once the CPU fan was disconnected. At least it took somewhat longer for the system to switch off...
- Intel's Core 2 Duo E6850 completed two out of ten benchmarks with a non-working CPU fan. This is clearly a better result than the Athlon 64 X2 6000+.
- Finally, the Pentium Dual Core E2160, which is a low-cost processor rated at a TDP of 65 W, managed to complete all ten benchmarks with the CPU fan disconnected! Compared to the 45 W of AMD's Athlon X2 BE-2350, this processor cannot possibly go as high as 65 W, as it would have shut down at some point.
The Pentium Dual Core E2160 is clearly somewhat more energy-efficient than specified, as it outperformed the direct competitor Athlon X2 BE-2350 in this extraordinary test. This also proves that it is certainly possible to passively cool a mid-class dual core processor and run applications with only a little bit of a performance penalty. All high-end processors, however, do require active cooling to remain reliable and deliver their full performance potential.