Digital-Daily : Cooling : coolers_p4_heatpipes

Comparison of coolers using heatpipes

Author: Aleksandr Mitrofanov
Date: 28.12.2003

Testing

Testing was performed on Abit IC7-G ; motherboard, Motherboard Monitor was used as a monitoring tool. Intel Pentium4 2.4 processor with D1 stepping, working on 3.0GHz on nominal voltage.

Also all coolers were tested in more difficult conditions: the processor was working on 3.6GHz at Vcore=1.65V.

Heating of the processors was made by two running copies of BurnP6. Two working applications allow to load a processor at full capacity (I should remind that D1 stepping processors support HyperThreading).

Then the tested system has been assembled in Inwin S506 case and power supply has been placed outside the case. The matter is that this power supply has a fan with adjustable rotation speed (dependent on temperature) and such power supply could influence testing results. If a cooler has its own thermal interface, this thermal interface has been removed and further measures were carried out with KPT-8 silicon-organic thermal paste.

Here goes the effectiveness of Pentium4 3.0GHz cooling.

The system was working steadily with all types of coolers. Zalman 7000 cooler and Themalright heatsink + Zalman ZM-F2 fan have shown particularly good results. Water cooling system conceded them only 4 C degrees. The most probable reason is poor effectiveness of aluminum waterblock.

As to Auras coolers, their effectiveness can be ranged as average (close to Tt Spark5 cooler or Tt Spark7). The reason is relatively weak fan, which is installed on CoolEngine-T6C and -T6C Golden models.

Then we increase voltage up to 1.65V and increase FSB frequency up to 300MHz. Now Pentium4 processors is working on 3.6GHz and is emitting at least 100-110W of heat.

The first testing was performed with Auras CoolEngine-T6C cooler. The temperature reached the value of 71C quite fast and the system shut down a minute after that. That is why I decided not to test knowingly weak CoolEngine-T6C-Golden. Zalman 7000C was the next: the system was working with him for 10 minutes with a processor temperature of 70C and then it restarted.

Anyway this result didn't surprise me; I was performing such tests before. The next one was Poseidon which was keeping processor temperature at 70C for two hours. The system was stable through all this time, but I cannot guarantee that the stability was achieved due to the Pentium4 internal overheat protection. I must remind that as soon as overheating occurs, Pentium4 is starting to "omit clock cycles" that leads to significant decrease of total performance but prevents further increase of temperature. And this "critical threshold" is different for different types of processors. That is for example for processors working on 3.0GHz at Vcore = 1.525V, the performance decreases when 77-80C temperature is reached (it was figured out in the last comparison testing of Pentium4 coolers).

And finally I installed Thermalright SP-94 heatsink with Zalman ZM-F2 fan. The result has outperformed all my expectations: the processor temperature did not exceed 67 degrees.

It is natural if a reader would ask the question: is the effectiveness of SP-94 heatsink worse or better than the one of "ordinary" liquid cooling systems, which have both brass heatsink and wateerblock? One more water inexpensive (worth ~$100) cooling system took part in our testing which has shown the result of 62.5C (we will review it later in our upcoming publications). It is obvious that more expensive and systems will demonstrate better results, but the fact is: Thermalright SP-94 prolongs life of "air" cooling systems. Actually this is achieved with hard labor, that is one has to give $50-55 for a heatsink besides some $ for a good (!) fan.

Surely this review will be interesting mostly for overclockers, which choose a cooling system for the future Prescott processors. Ordinary users should not worry about anything. When these processors are issued, Intel will either overcome technical difficulties of increased heat emission or will design an effective "box" cooler.

If we make first brief conclusions, they would be the following. I can recommend only Thermalright SP-94 and Zalman 7000-Cu or -AlCu for purchasing. Concerning Poseidon system, it can be bought for not more than $30. Concerning Poseidon system, in spite of their "technological" look, their effectiveness is far from being optimal and it is difficult to recommend it for purchasing. However I haven't found prices of -T6C(Golden) in the net, and if it fits reasonable limits (say $15) these coolers will find their customer for system of "average performance".