Enermax NoiseTaker 475 PSU

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March 24, 2004 by Mike Chin

Product
Enermax NoiseTaker EG475P-VE SFMA
470W ATX 12V v1.3 power supply
Manufacturer
Enermax
Sample Supplier
Maxpoint
Market Price
~US$100

Enermax is one of the very first names that comes to mind when you think of computer power supplies. They were the first to merchandise the power supply as more than a gray mysterious gray box that hums in the back of the PC. With their signature metallic blue paint job, dual-fans and wire grills, they have long been among the most visible of PSU brands.

The first Enermax PSUs I used and examined starting about three years ago did not fare well for PC silencing, despite the whisper quiet promise of their marketing. The fans started off at a very quiet level but then ramped up to much higher speed, due mostly to a fan controller that increased fan speed linearly with internal temperature. One of SPCR's first articles was an examination of how to change this fan speed behavior in the Enermax and other thermal fan PSUs.

Technology companies can never stand still, and Enermax is no exception. They have made changes to their extensive PSU product range. A new series, called NoiseTaker, is named for what it is supposed to do: Take the noise away. Maxpoint, the US distributor, suggested it was time for SPCR to take another good look at Enermax, and sent over a NoiseTaker EG475P-VE SFMA 470W ATX 12V v1.3 power supply.

As you can see, looks have not changed much. It is still that nice metallic blue, and the recessed wire grills are still gold-colored.

This new power supply has many strong features, and a 3-year warranty for all units purchased after February 1, 2004. Among the feature highlights:

FEATURE & BRIEF COMMENT
Smart fan: After PC shuts down, cooling fans keep running for at least 2 minutes to effectively cool down parts and hardware inside PSU and PC, ensuring longer product life. It is not clear whether this is truly a useful feature, but it probably can't hurt.. Perhaps for hot PCs in hot environments...
Separate 12V rails: Two independent 12V rails supply to MB/CPU and drives in order to provide stable and clean current to noise-sensitive devices, such as: CPU, add-on cards. Meets UL 240VA safety requirements An interesting twist on independent 3.3V, 5V and 12V rails. With power-hungry VGA cards and CPUs drawing on the 12V line, two independent 12V lines is probably a good idea.
ATX 12V V1.3 compatible: Support latest P4 and Athlon 64 platforms. For P4 platforms use 865 (Springdale) & 875 (Canterwood) chipsets and even new P4 Prescott and AMD Athlon 64 or later CPU. This is only the 2nd PSU line we've looked at that is V1.3 compatible (the first being the Seasonic Super series); generally a good thing, with higher current capacity for the 12V line.
S-ATA connectors: Connect your system to the faster S-ATA interface for better performance. Two on one lead, obviously useful.
Manual and automatic fan speed control: 8cm & 9cm fans automatically controlled by thermostat plus rheostat control over 8cm fan. Enable users to keep the balance between cooling effect and acoustic noise. The range of the manual controller is affected by the thermistor: Both maximum and minimum speeds ramp up and down with temperature.
Extra Power connector: Extra 4-pin power connector provides high-end graphic card with stable current. This appears to be dedicated, but it is just a single lead in a more insulated cable.
Reliability: OCP, UVP, OVP, OLP, OTP, and SCP circuits ensure system well-guarded from any dangers. Maximize safety for your hardware and valuable data. Generally, the more safety approvals the better. Means good international distribution, at least.
Copper-shielding: Effectively reduces electro-magnetic interference that might affect MB and CPU from normal operation. (Valid for models with 370W and higher total power) Not sure where this copper is. In the cable braiding?
Dual Fan: The best cooling method for PC system, and is strongly suggested by AMD. SPCR doesn't regard the dual-fan design so highly, but the proof is in the noise and the cooling.
Silence: Acoustic noise is successfully reduced with two fans giving more airflow in less rpm and smooth mechanical design of fan guards. See comment directly above.
FM & FC functions: RPM signal of 8cm exhaust fan is provided; EG xxx AX-VE SFCA/FCA models allow MB to on/off control 8cm exhaust fan. MB control is an interesting function; not on this sample.

And the official NoiseTaker Specifications:

AC Input
95V~135V or 180V~265V (selected by slide switch)
47~63 Hz; 60A max. on cold start
DC Line
+3.3V
+5V
+12V1
+12V2
-12V
+5Vsb
Ripple
50mV
50mV
120mV
120mV
120mV
50mV
Tolerance
°5%
°5%
°5%
°5%
°10%
°10%
Output
34A
40A
16A
15A
0.8A
2.5A
Combined
280W
372W (31A)
9.6W
7.5W
Total
460W

It is a powerful unit according to the specs. 372W on the 12V lines alone is a lot of power. But note that the numbers on the left don't add up to 470W. This means 372W on the 12V line is available only if the rest of the lines are putting out 98W or less. Conversely, 280W is available on the 3.3V and 5V lines only if the other lines are not drawing more than 190W.

Interestingly, the operational temperature is given as 0~40°C. This is much stronger than what is specified for most Enermax PSU models:

"0 ~25°C for full rating of load, decrease to 80% rating of load at 40°C; decrease to zero Watts O/P at 70°CC"

If the unit can really deliver 470W at 40°C, it is a very powerful power supply.

FAN CONTROLLER

This feature is one of the most important from a silencing point of view. As mentioned earlier, earlier Enermax models had a linear thermal controller that spun up the fan unnecessarily even when not needed. The NoiseTaker shows more sophistication. From the manual comes this description and graph:

"RPM of 8cm & 9cm fans can be manually adjustable (sic) from low to high rpm level according to user°s need to keep the balance between acoustic noise and cooling effect. In addition, we also feature thermal control circuit to NoiseTaker series power supply to regulate both 8cm and 9cm fans to adjust to various system loading conditions and provide necessary cooling. 8cm fan rpm can be monitored by BIOS or software through the output of tachometer signal."

As with most manual fan speed controllers, this one is tied to a thermistor that determines both the minimum and maximum speed available. With the PSU at 40% load or less, the range is from 27% to 60% of maximum fan speed; at 100% load, the range is 84% to 100% of max fan speed.

Note that the term SYSTEM LOADING in the graph is rather vague. The graph suggests that the fan controller somehow varies fan speed in accordance with system load; it does not. As with all automatic fan speed PSUs on the market, the fan speed is tied to the temperature seen by a thermistor (a resistor whose value varies with temperature) inside the PSU. Certainly, temperature is affected by system load, but there is no direct controlling relationship between system load and PSU fan speed.

The presence of the long plateau on the left side of the graph is a good sign. It means that the NoiseBlocker's fan stays at minimum speed up to some preset temperature, and speeds up only beyond this point. It is the basic approach taken by almost all the PSUs that strive for lower noise: The fan speed is increased on when it is really needed to keep temperatures inside the PSU in a safe zone.



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