Dual fans on a PSU? Is that better?

I was looking at soem PSUs and i saw some of them have dual fans. One on the top and one on the side. I was thinking where is that fan on the top going to push the air out too? I mean do u have to have a hole on the top of ur case so this works?

no, the psu that have the extra fan are mounted so that they blow inside the psu, not exhausting hot air, and they are ususally mounted on the bottom of the psu, not on the top

Is that is good having two fans? Would that be benificial?

more airflow, better cooling. so i would say it would be beneficial,

The noise level can go up as well though. FYI, Vantec makes a "stealth" PSU with 3 fans. The problem is...after 3 fans, the PSU is anything but "stealth."

It's usually not bad though, just check some reviews and make sure it's quiet.

If you even care...*shrug*

I've owned an Enermax with 2 fans and a Fortron with 1 fan. The Enermax puts out *slightly* more air than the Fortron, but at the cost of being significantly louder IMHO. To me, the noise doesn't seem worth the small advantage in cooling.

I wouldn't buy a PSU over another just because it has an extra fan.

www.pcpowercooling.com/pdf/Turbo-Cool_510_vs.pdf compares a PC Power & Cooling 510W to a competitor's 500W+ PSU and says that the second fan in the latter is ineffective. I'm not sure, but I think that's an Enermax.

yeah, it looks exactly like my old enermax 550. I have used both the pc power and cooling 510 and the enermax 550 and the pc power and cooling 510 is easily a better PSU. Its rails NEVER fluxuated. I added a 2nd fan to the PSU (Through fan stacking on the exhaust) and now it is cool to the touch were with the stcok fan it used to be warm. Either way it was putting out rock solid rails.

Something worth mentioning.

Some of those multi fan PSU have low efficiency components
which create more heat. That's why they need the extra
airflow.

Susquehannock said:

Something worth mentioning.

Some of those multi fan PSU have low efficiency components
which create more heat. That's why they need the extra
airflow.

Click to expand...

o i didnt know about efficiency created more heat i was looking at some PSUs and the highest i remember seeing is 70% efficiency.
Is that good and also what is the highest efficiency?

The efficiency that is described relates to the power factor. An active PFC (power factor correction) is able to have the highest efficiency since it can properly correct for the inductance of the power supply. This inductive phase angle causes the power supply to draw more amps than it normally would.

If the efficiency is 70%, then if the components in your system are drawing 200 watts, then, the power supply would be demanding 260 watts from the wall. The power supply would also have to disspate this in the form of heat.

Some power supplies offer a passive PFC, which uses a parallel bank of capacitors to rectify the power factor to achieve a efficieny rating of around ~70% or so.

PC Power and cooling offers 95-99% efficiency through its active PFC and is much more efficient than standard power supplies. This efficiency, however is expensive, but may pay for itself in a few years in power savings.

it cools it better and it also actas like a case fan to your case

georgelogy said:

The efficiency that is described relates to the power factor. An active PFC (power factor correction) is able to have the highest efficiency since it can properly correct for the inductance of the power supply. This inductive phase angle causes the power supply to draw more amps than it normally would.

If the efficiency is 70%, then if the components in your system are drawing 200 watts, then, the power supply would be demanding 260 watts from the wall. The power supply would also have to disspate this in the form of heat.

Some power supplies offer a passive PFC, which uses a parallel bank of capacitors to rectify the power factor to achieve a efficieny rating of around ~70% or so.

PC Power and cooling offers 95-99% efficiency through its active PFC and is much more efficient than standard power supplies. This efficiency, however is expensive, but may pay for itself in a few years in power savings.

Click to expand...

Power factor is subtly different from the "efficiency" of a PSU. An efficiency calculation takes the input power and the output power and divides them to get the percentage of useful energy derived from X amount of energy input into the PSU. Power factor is a measure of the phase angle deviation of the current in the device with respect to voltage, so what you said about it is correct but it is not efficiency.