http://www.xbitlabs.com/articles/cas...50-gold_3.htmlWorking with our APC SmartUPS SC 620, this PSU was stable at loads up to 360 watts when powered by the mains, but could not switch to the UPSís batteries even at 280 watts.
http://www.newegg.com/Product/Produc...82E16842101130APC changes the technology while leaving the model numbers the same. The older units are completely silent during normal operation since the fan only runs under certain conditions, such as when the unit is running off of battery. The newer units have a fan that is always on and the fan is quite loud for an office environment. It is as loud as a noisy computer fan. You can hear it from over 50 feet away. This isn't an issue for server rooms, but it might be an issue for rooms where you don't want the constant humming of noisy fans filling the room.
http://www.silentpcreview.com/forums...45834&start=30Well I've had my SMARTUPS 1000 for a couple months now. The only noise is the buzzing/coil noise from it, but that can be very annoying when the room is completely silent outside of the ups. I notice the buzzing can be louder or quieter, probably dependent on the electrical system in the house itself. I've never found a UPS that did not have buzzing so far, but it is definitely something that is drowned out by any other noise. I'd say this and the APC RS900 have a similar buzzing loudness.
And to think I was about to get a V300 drive I saw on sale yesterday.