Dell server has option to switch off PFC in BIOS?

[NiHaoMike]

So I was working on a new Dell server (adjusting the fan settings because a network card was overheating) and I noticed that the BIOS had an option to disable power factor correction. Since rackmount servers are pretty much always used in commercial settings and PFC is pretty much always a good idea there, why would there be an option? Is it for use with a UPS system that would make the PFC a waste of efficiency? (I have no idea if it actually does anything and I left it enabled since it is in a commercial setting.)

That server also had options to throttle down the CPUs in order to limit power, which apparently can be changed in real time over the network. That can greatly reduce the battery capacity needed for a UPS and it would be nice if it was available on more ordinary machines.

 

[Bobnova]

That's rather odd. Is it a 240v-only PSU? Curious from a internal voltage standpoint.

 

[ivanlabrie]

Seems like a strange feature...I'd like to know more about that, since I do have PFC and an anti surge thingie.

(in before the trolling begins)

 

[NiHaoMike]

Pretty much everything in that room ran on 208V, except the air handlers which are 480V. I also wonder if it's possible to completely disable PFC with 120V input and no voltage doubler. It's apparently possible to play some tricks with digital PFC controllers to cut off the PWM near the zero crossings where the instantaneous efficiency is low, yet still end up with a pretty good power factor.

 

[Automata]

What server was it? My 120v R710 and R510 do not have this option unless I'm not looking in the right place. I know the power supplies have a lot of electronics in them for monitoring and control, so I wouldn't put it out of the realm of possibility for enabling/disabling features.

I can check again in the BIOS if you remember what the feature was called and/or where it was. Powering down a bunch of virtual machines and waiting for the five minute POST is a bit annoying.

 

[Bobnova]

My experiences and the experiences of some other reviewers that do non-PFC units sometimes is that most 240v PSUs will start and run on 120v, but will explode in short order if loaded. They don't appreciate the extra amps required on the primary side to get the output up to par.

I'd be interested to know the server and also the PSU model number. Some pictures of it too really, I want to know how it communicates with the BIOS.
Hell some shots of the BIOS would be interesting too