replacing a 2-wire fan out of psu that states supports fan speed monitoring!?

[kgs]

I have a recent Powmax LP8800-C psu that states on the box "supports fan speed monitoring".

It is an ATX 350W that "complies with ATX ver 2.03 and ATX ver 1.1"

The fan inside is the psu is also a Powmax, a 2-wire FM802512M, DC12V, 0.15A, Brushless, 0209, soldered to the psu board in the box.

The psu only has a 4-pin and a 20-pin connector, besides the molex connectors that supply the power to the devices .

Where would the rpm monitoring information come from, if it indeed does, and how is it transmitted to the mobo? (The 4-pin or 20-pin connectors are the only options as far as I can tell)

This is the reason I ask:

I have researched cooling for the new P4 system I am building, upgrading from my P3. My current P3 now is without a 4-pin connector, so I just have the 20-pin to connect which is req'd. So I do not know how the fan speed monitoring of my psu would work, if it does. Is the signal through the 4-pin 12V, or the 20-pin connector on my new P4C800E-Deluxe mobo?

I want to remove the supplied stock fan in the psu and replace it with a Vantec Stealth to match the 2 others in the case for intake and exhaust. It is quiet. It definetely allows fan speed monitoring, if connected directly to the 3-pin PWR_FAN header/connector I have on my new P4C800E-Deluxe mobo.

I would like to know first how the rpm is transmitted, ie through what cable.

Secondly, is it possible that the rpm is calculated on the psu board (by voltage or something?

Because I want to disconnect the current 2-wire fan out of psu that states supports fan speed monitoring!? and replace it with the Stealth by plugging it into the 3-pin PWR_FAN.

Would this cause any malfunction in the psu, and/or would a faulty rpm psu fan rpm signal be sent to the mobo, which would cause a faulty reading, even if I had the 3-pin PWR_FAN mobo header/connector attached directly to the fan?

As a last resort, I would re-solder the Stealth onto the psu with 2-wires like the stock Powmax fan. Then possibly try to connect the rpm signal wire only to the 3-pin PWR_FAN mobo header/connector, which would be a bonus. getting the right rpm reading, if any would be a bonus too I think, but I will have this fan, and quiet IS my goal.

I need to know PDQ because I'll be shopping in a dozen hours.

 

[mechBgon]

Bigger picture: Powmax power supplies are generally regarded as pretty low in quality. You're building an upper-end system and planning to overclock, so may I suggest a better unit? Enermax, Antec and Sparkle Power are well-regarded for having good quality. I'd recommend something in the 400W+ range, although some folks say that's overkill. Then again, some folks say it's underkill

Enermax has some models with a manual fan-speed adjuster on the outside rear, you might look into those. Save that Powmax for an old Celeron 600MHz system or something

 

[kgs]

dunno yet

i just got this a while ago cause my old P3/cel600 psu died. it cost me the same price on sale as each of the Stealth fans I just bought.

 

[MichaelD]

Originally posted by: kgs
dunno yet

i just got this a while ago cause my old P3/cel600 psu died. it cost me the same price on sale as each of the Stealth fans I just bought.

Heh, that should be a major tip off for you!!! When your PS costs the same as a case fan, that is a very, very bad thing!

Get an Antec/Enermax/Sparkle.

 

[Jhhnn]

PSU's that actually support fan speed monitoring have a separate 3 pin connector that plugs into the mobo, usually with just two wires, monitor and ground, power being supplied from inside the unit itself. Doesn't matter what the box sez...

Installing the vantec fan as you've proposed will work and provide monitoring, too. Powmax supplies definitely aren't the best, so plan on upgrading to one of the suggested brands in the near future. Heroichi (HEC) and Delta also make good stuff, along with a few others. sparkle and Fortron/source are the same thing, just different brand names, also good- their new models with 120mm fan are extremely quiet, and relatively inexpensive...