The Zalman Twins: 9500 & 9700 Air Tunnels

Cooling Results

The Zalman 9500 and 9700 are both excellent performers in CPU cooling at stock speeds. However, as overclocks were raised, neither cooler was particularly outstanding in the ability to cool the CPU under stress conditions. To be as fair as possible all overclocking tests were run with the 9500 and 9700 fans at the highest speeds they could be pushed to with the Fan Mate 2 controller. These fan speeds also generate a great deal more noise than the low speed settings on either cooler.


Where the very good Intel stock cooler keeps the X6800 at 41C at idle, the 9500 can manage an excellent 30C, with the 9700 doing even better at 28C. This is not quite as cool as the Tuniq Tower 120 at stock idle, but it is among the best performance we have seen at stock idle speeds. As processor speed increases, however, the Zalman starts dropping rapidly in efficiency. The higher the speed goes, even at idle, the greater the cooling performance delta between the 9500/9700 and the leading Tuniq Tower 120

At 3.73GHz the retail HSF is running at 56C, compared to 42/38C with the Zalman 9500/9700. The performance at idle with both Zalman cooler is quite good at stock speeds, but performance drops fast with increased CPU overclocking. Both Zalman coolers reach rather average overclocks, considering they are very expensive coolers. The 9500 tops out at 3.81 GHz and the 9700 tops out at 3.83GHz. Many of the top coolers we have tested have done better.

It is easy to measure the effectiveness of a cooling solution at idle - when the computer is doing nothing except running the temperature measurement program. It is more difficult, however, to effectively simulate a computer being stressed by all of the conditions it might be exposed to in different operating environments. For most home users CPU power is most taxed with contemporary gaming. Therefore our stress test simulates running a demanding contemporary game.

The Far Cry River demo is looped for 30 minutes and the CPU temperature is captured at 4 second intervals with the NVIDIA monitor "logging" option. The highest temperature during the stress test is then reported. Cooling efficiency of the Zalman 9500 and 9700 under stress conditions was compared to the retail HSF and other recently tested CPU coolers. Once again the well-regarded Tuniq Tower 120 was the top air cooling solution, with the TEC/air hybrid Monsoon II Lite as the top performer. Both Zalman coolers were very average in performance among the coolers we have tested and well behind the Tuniq and Cooler Master at the top of the air cooling chart.


The Tuniq keeps the CPU at 34C under stress at stock speeds, where the Zalman 9500 manages 39C and the 9700 does better at 36C. However, the same pattern emerges under stress testing that we first saw under idle conditions: as the overclocked CPU speed increases the cooling effectiveness of both Zalman coolers drops rapidly. By 3.83 GHz, which is the highest overclock the 9700 could reach with stability, the Tuniq is at 50C compared to the 5700 at 59C. The 9500 at its highest overclock of 3.81 GHz is at 59C. Both Zalman coolers appear to be optimized for excellent performance at or near stock speeds. While the Zalman coolers are among the top performers in cooling at stock idle and load, as speed increases their effectiveness drops rapidly.

As stated many times, the overclocking abilities of the CPU will vary at the top, depending on the CPU. This particular CPU does higher FSB speeds than any X6800 we have tested, but the 3.9GHz top speed with the Tuniq is pretty average among the X6800 processors we have tested with Tuniq cooling. A few of the other processors tested with the best air coolers reach just over 4 GHz, but the range has been 3.8 to 4.0GHz. Stock cooling generally tops out 200 to 400 MHz lower, depending on the CPU, on the processors tested in our lab. The 3.83 GHz with the Zalman 9700 and 3.81 GHz with the Zalman 9500 - both achieved with the cooler fans at their highest noisie levels - are average at best. We would expect premium-priced CPU coolers to perform better.