Vigor Monsoon II Active TEC CPU Cooling System Review

Testing

Testing the Vigor Monsoon II active TEC CPU cooler proved to be more of a challenge than I was expecting.  As I said earlier, the Monsoon II active TEC CPU cooler isn’t designed for extreme overclocking, sub-zero temperature operations.  It is a high-performance HSF that uses a medium size Peltier device to enhance the cooler’s overall cooling capabilities.  The control module is programmed to maintain a target CPU temperature, which should never drop below 25°C.  Initial tests using my standard test procedures at 24°C ambient room temperature, produced good results but clearly not sub-ambient.

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The key measure of a heatsink fan’s performance is how well it can cool the CPU.  This is typically measured by subtracting the ambient air temperature from the CPU temperature, which results in a differential temperature (referred to as the Delta T).  The closer the CPU temperature is to the ambient air temperature the better (smaller Delta T).  And when some form of active cooling is employed, there is the potential for temperatures to drop below the ambient temperature (-Delta T). 

The performance of most traditional heatsink fans and water-cooling systems that rely on convection cooling changes linearly with the ambient room air temperature (at least within the temperature range of most CPU operation).  If the ambient air temperature goes up 10°C, then so will the CPU temperature (Delta T remains the same) and vise versa.  However, with active TEC cooling this is NOT the case.  To test the true potential of the Monsoon II active TEC cooler required a slightly modified testing setup… 🙂

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In this configuration, a 4′ duct is used to route the warm exhaust air coming out the back of the Monsoon II cooler around to the front where it is sucked back in.  By carefully positioning the duct, just the right combination of warm recycled air and cool ambient air can be mixed to simulate a much warmer operating environment.  Doing this to a normal HSF would kill its performance, but when I fed the Monsoon II warmer air its operational curve shifted into the active mode, which resulted in better performance — not worse!

The Vigor Monsoon II active TEC CPU cooler was tested on an open frame Athlon64 K8 test rig consisting of the components listed below.  The ambient room air temperature was maintained at 24°C ±0.5°C during the first series of tests and artificially increased for another set of tests.  The CPU was loaded by running Folding@Home 24/7. 

• Asus K8N-E Deluxe nForce3-250 motherboard
• AMD Athlon64 3200+ (0.13 mm Newcastle core)
• Seasonic SuperTornado 400 watt ATX power supply
• (2) Corsair CMX512-3200C2  DDR RAM
• ATI Radeon 9800 Pro
• WD800JB IDE HDD
• Sony 16X DVD, FDD
• Windows XP Pro with SP1

To facilitate taking more accurate CPU temperature measurements I attached a very small Omega thermocouple to the side of the Athlon 64 IHS with Arctic Alumina thermal epoxy.  This temperature should correlate well with the Monsoon II’s internal temperature sensor as the cooler’s base plate is in direct contact with the IHS.  The measurement equipment used during testing included:

• CPU/IHS — Barnant Model 115 digital thermometer (accuracy +/- 0.4º C)
• Ambient air — Barnant Model 115 digital thermometer (accuracy +/- 0.4º C)
• TEC voltage — FLUKE 87 III digital multimeter (accuracy +/- 0.05% of reading)
• TEC current — FLUKE 87 III digital multimeter (accuracy +/- 0.2% of reading)
• Extech Model 407736 digital sound level meter (accuracy +/- 1.5 dB)

The following data is presented for comparative purposes only.  Your actual results may be different depending on the variables unique to your system (CPU, overclock, ambient temperature, case air flow, temperature monitoring, etc).   Tests were performed under two different sets of testing conditions: first with a 24°C ambient temperature and then with the ambient temperature artificially raised to 36°C.

Display — Monsoon II controller digital display

TEC V — DC voltage applied to the Peltier device

TEC A — DC current flowing thru the Peltier device

CPU — Temperature reported by Asus PC Probe utility (internal diode)

Tc — Temperature obtained with calibrated thermocouple attached to IHS

Delta T — Fully loaded Tc temperature rise above ambient

dBA — Sound pressure level recorded 3′ away (background ~30 dBA)

The performance of the Monsoon II cooler was good during the first set of tests with an ambient room temperature of 24°C but wasn’t as good as some other high-performance HSFs currently on the market.  With the relatively low ambient temperature the Monsoon’s TEC cycled on and off (off most of the time) and the fan cycled between low and medium speed (low most of the time).  In this mode the cooler is operating pretty much as a standard HSF with very little assistance from the TEC.

Artificially increasing the ambient room air temperature to 36°C (recycling warm exhaust air) forced the Monsoon II into active mode.  This is also a more realistic internal case temperature.  Under these conditions performance was outstanding as indicated by a negative Delta T (-3.4°C).  Yes, the CPU (cold plate) temperature was actually lower than the ambient room air temperature.  In this active mode the TEC was turned on almost constantly and the fan speed cycled between medium and high (mostly medium).

Notice that the Peltier device pulls less current when it is on all the time versus cycling (mostly off).  This is because the TEC pulls more current when it is cool and pulls less current as it heats up (internal resistance of the thermocouples increases).  Power consumption for the Monsoon II active TEC cooler is a minimal 5 amps on the +12V rail so a large, dedicated power supply is not needed.  MACS recommends using a minimum of a 350W PSU (I would go with at least a 400W, high-quality PSU).

Details about the MACS controller programming are proprietary but from my testing I was able to glean the general operating characteristics for the Monsoon II active TEC cooler.