Cooling Efficiency Tests

During Linpack tests inside a closed system case using the “weakest” cooling system of the today’s testing participants  we managed to overclock our 45 nm quad-core processor only to 3.5 GHz (+16.7%). The nominal processor Vcore was increased to ~1.375 V in the mainboard BIOS (+19.6%):

During Unreal Tournament 3 tests even the weakest cooler ensured processor stability during CPU overclocking to 3.85 GHz at1.5 V Vcore.

The results are summed up on the diagram below:

First, I would like to say a few words about the outsiders of this test session. Quite naturally they are CNPS8700 NT and Thermaltake V1 AX. Moreover, the efficiency of the latter barely depends on the rotation speed of its fan, because when we spec it up from ~1390 to ~2080 RPM, the CPU temperature got only 1°C lower in Linpack and 1~2°C lower in Unreal Tournament 3. If I had to choose between these two coolers, my preferences would go to Zalman CNPS8700 NT, for being smaller and quieter. Although it is a little more expensive.

You may find it strange but the next one in efficiency is Zalman CNPS9700 NT, showing 5°C better CPU temperature readings. It is pretty sad that its exact replica – Zalman CNPS9700 LED, and before that Zalman CNPS9500, used to be the best air coolers and now are only a little ahead of the outsiders at best. We wish the Korean company had made something more efficient than what they already have in their product range.

Thermaltake coolers from MaxOrb series are about 3~7°C more efficient than Zalman CNPS9700 NT. As I have expected, the copper cooler model couldn’t demonstrate any significant advantage over the copper-aluminum model. At maximum fan rotation speed the coolers are almost equally efficient and at the minimal fan rotation speed MaxOrb EX is only 1°C better in Linpack 32-bit, which may be regarded as a measuring error. MaxOrb heatpipes that are not arranged in the most efficient way on leaving the base do not let the cooler show its real potential. Unfortunately, it can only be fixed in design and production stage.

And the leader of our today’s test session is ZEROtherm ZEN FZ120 that turned out 3°C more efficient than the best of the competitors. This is a really small difference, but ZEROtherm cooler achieves it without any modding extras, at a lower price and with lower noise.

Speaking of noise. Let’s check out the acoustic readings now.