PSU Heat + Rails question

[Dc5e]

Okay, I've been running my duallie setup for quite awhile now, and recently i've just ordered some cooler master heatpipe's for my cpus which mean i should be able to go passive cooling on the cpus.

So the next thing I want to deal with is my PSU. I have the Fortron FSP-550PLN and I know that this has two 12v rails. So first off, when my computer is running idle, the PSU fan runs at med or low? speed and its shooting out fairly warm air. But when I put full load on my cpus, the powersupply eventually heats up, making the powersupply fan go on high and making it shoot out hot air. I'm guessing it heats up because i'm drawing more power, right?

Also, I'm not exactly how two rails differ from one. I know that they're two separate supplies and I guess the circuitry are separated to do so. But how are the rails split? Is a set of molex connectors coming from the power supply one rail?

If so, then would my powersupply actually run cooler if the load is better distributed between the two rails? Rather than having one rail supply most of the power? Or would it make little to no difference at all?

And any other ideas to help silence this beast yet keep it cool would be helpful.

[Oklahoma Wolf]

It's probably ramping the fan up due to more power draw on it combined with extra heat inside the case from two CPU's heating up under load.

The two 12v rails are probably split with one dedicated to powering the CPU's and the other powering the rest of the system. Not sure if the other 550w unit with the single 36A 12v rail would help any with keeping the fan speed down - keep in mind these are meant for servers, and keeping the fans quiet wouldn't have been a priority for Fortron.

About all I can suggest is to experiment with fan swapping. If nothing else, SilenX has a new 600w Fortron based unit with a quiet fan. IIRC, it has a single 36A 12v rail like the 550w units, but more powerful 5v and 3.3v rails.

[Dc5e]

Okay, I guess that just hits the answer. I probably won't do much. Hopefully after installing my new heatsinks that are coming soon, heat will probably be expelled out of the case easier than having most of it go through the powersupply.