Written By:
Date Posted: October 7, 2002

The ZM300A-APF

The final item which Zalman sent me was the ZM300A-APF - a 300 Watt CNPS PSU (Power Supply Unit.) There is a thermistor (essentially a resistor which responds to heat,) which is attached to the heatsink in the PSU. To be honest, when first looking at this PSU I had many doubts - 300 Watts really isn't a lot of power - especially when you're running not only an Athlon, but also numerous other devices. I was quite impressed with this PSU though, and certainly have good things to say about it.

Performance

My Machine:
CPU: Athlon 1700+ with Arctic Silver 3
Motherboard: Abit KR7A-Raid - socket thermistor touching the bottom of the CPU
Case: Fong-Kai 320-Black, 1 case fan running
Prime95 run for 20 minutes, Room Temperature is 22 degrees Celcius
Comparison Cooler: Vantec CCK-6027D

Before we look at performance, let's see if this so called "CNPS" works - if the Computer Noise Prevention System isn't just a gimmick.

The Deafness Research Foundation (http://www.drf.org) provides the following information:

Decibel Level Example

30: Quiet Library, soft whispers
40: Living room, refrigerator, bedroom away from traffic
50: Light traffic, normal conversation, quiet office
60: Air conditioner at 20 feet, sewing machine
70: Vacuum cleaner, hair dryer, noisy restaurant
80: Average city traffic, garbage disposals, alarm clock at two feet

THE FOLLOWING NOISES CAN BE DANGEROUS UNDER CONSTANT EXPOSURE!

90: Subway, motorcycle, truck traffic, lawn mower
100: Garbage truck, chain saw, pneumatic drill
120: Rock band concert in front of speakers, thunderclap
140: Gunshot blast, jet plane
180: Rocket launching pad

They say that at 120 db (Decibels) hearing loss occurs after 9 seconds, and at 96 dB, hearing loss occurs after 37 minutes.

The question becomes for me - how do I measure these while at the same time preventing excess noise from being registered, as well as the air from a fan blowing across the microphone and giving it a false reading. I held the Sound Level Meter (Analog - purchased at Radio Shack, CAT. NO. 33-2050, Weighting set to "C", Response set to "Fast".) The sound level meter was placed approximately 2 inches away (perpendicularly) to the fan as to reduce the possibility of the airflow causing a discrepancy. Please note that these values are much louder than what you would hear when a case is all closed up.

The CNPS3100-Plus (when it's fan resistor was removed) registered at 66 dBs
The CNPS5100-Cu (without the Fan-Mate) registered at 72 dBs
The comparison cooler (Global Win delta-style fan) registered at 81 dBs

We can see here that the coolers registered in between an Air Conditioner or Sewing Machine and Average city traffic. Once again, take into consideration that a case will muffle the sound.

Now let's see how these stack up performance wise:

The room was kept at a constant 22 degrees Celsius; the motherboard registered the case temperature at 35 degrees Celsius. We'll first be demonstrating the comparitive temperatures of low and high speed fan settings for the CNPS5100-Cu.

Idle Temperatures (degrees Celsius)

Load Temperatures (degrees Celsius)

With the fan at its highest speed on the Fan-Mate, the CNPS5100-Cu had:

An idle of 39 Degrees C
After the Prime95 test, the CPU was at 45 Degrees C

With the fan turned to its lowest point, the CNPS5100-Cu had:

An idle of 45 degrees
After the Prime95 test, the CPU was at 52 Degrees C

I found that with the resistor on the fan included with the CNPS3100-Plus, the temperatures were not comparable to those obtained by the other coolers, so only the temperatures with the fan set to its highest RPM have been recorded.

Idle Temperatures (degrees Celsius)

Load Temperatures (degrees Celsius)

The CNPS3100-Plus had:

An idle of 52 Degrees C
After the Prime95 test, the CPU was at 58 Degrees C

The CCK-6072D had:

An idle of 39 Degrees C
After the Prime95 test, the CPU was 43 Degrees C

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