imac is APFC power?

I just purchased a Cyberpower CP850PFCLCD. it's a 510watt UPS and it's a Pure Sinewave which I have been told is the best for iMac's with PFC Power supplies. I paid $119.99 at BestBuy Canada.

I commented on another discussion regarding this topic.

The good thing about Mac's Energy Saver preference panel and the CyberPower UPS is that you can set it up to self shut down if the power goes off. I leave my iMac on 24/7, so I might be out of my house when the power goes off, or just taking a shower. I think you're overlooking how useful it can be when you're not there.

Also, do you realize that a pure sine wave UPS is probably not that important, unless your intent is to run for a long period of time without power from the Grid.

1. All Macs have an Active Power Factor Correction power supply (called PFC), which allows them to be used with a wide range of voltage and electrical quality. I believe this was implemented in 2007
2. UPS manufacturers want you to believe that pure sine wave models (more expensive) are necessary for PFC computers. BUT, that's only if you're running for a long period of time (say a server). You have already said you intend to shut down your computer (or as I recommend, set up for auto-shutdown), so we're talking just a few minutes.
3. A well designed UPS (which we're discussing, not some off brand piece of junk), the UPS should be able to transfer from external power to battery in a few milliseconds. Mine has the spec of 8 milliseconds. Here's where the problem occurs and where you might have an issue. If you do not have enough "headroom" on your UPS to handle all the wattage being drawn, even a pure sinewave UPS will cause a dropped power load.

So if your intent is just short-term power, long enough to shut down, my suggestion is you don't spend money on a pure sine wave UPS, and up the rated wattage of your UPS to handle that instanteous surge where the APC may draw a full load at the moment of switchover. You will get much larger UPS for much less money if you ignore the pure sinewave versions.

I went with a non-sinewave (but a simulated one) with 600 watts which is huge overhead to my 300 watt iMac (at it's highest draw), and a small 15 watt draw of an external Time Machine drive.

I tested my system by shutting off the relay to my home office, and I got about 10 minutes of power for both (but the screen was on the iMac, which might be different if it were in display sleep mode). The battery worked flawlessly, though I probably wish I had gone with a 1000 watt version, just in case the shutdown takes a long time.

Don't overpay for what you don't need. If you want to protect all of the devices you want, spend on reserve power, not on a pure sine wave.

A 510 watts UPS with an iMac that draws 300 wats may be cutting it close. You may have only 5-7 minutes before you lose power.

For a MacBook Pro? Practically any UPS will suffice, including this one: APC BE350G

A sine wave is overkill for the MacBook's power supply. If you are partial to Cyberpower they have far less expensive models that create a stepped sine wave, but with much greater capacity such as this one: CP825AVRLCD

Either of these would be adequate even for an iMac. A UPS itself is only necessary when the power fails and your battery dies, and all portable Macs sleep in an orderly fashion when that occurs. If you want a UPS for a desktop, you would want one with a USB connection to inform the Mac it's running on backup power, and to shut it down before the battery dies (here is one). That is not necessary for a MacBook.

John Galt wrote:

For a MacBook Pro? Practically any UPS will suffice, including this one: APC BE350G

A sine wave is overkill for the MacBook's power supply. If you are partial to Cyberpower they have far less expensive models that create a stepped sine wave, but with much greater capacity such as this one: CP825AVRLCD

Either of these would be adequate even for an iMac. A UPS itself is only necessary when the power fails and your battery dies, and all portable Macs sleep in an orderly fashion when that occurs. If you want a UPS for a desktop, you would want one with a USB connection to inform the Mac it's running on backup power, and to shut it down before the battery dies (here is one).

I assumed that the OP was using an iMac, since this is an iMac Discussion Community.

And I completely agree with the USB connection. At least for the CyberPower brand, OSX's 10.8.2 Energy Saver preference panel accurately reads the brand of the UPS and allows me to set up a force shutdown time, while running on the battery. That should save the life of my hard drives.