Do Intel iMacs Require High-Priced UPSs?

Question

I'm in the market for a UPS for my new iMac. I've never used one before, but I've experienced enough power glitches to now "graduate" from my trusty old surge suppressors.
In the past, I've leaned towards APC surge suppressors, so I decided I'd look into APC UPSs. In doing my homework, I came across a rather interesting, and potentially disturbing, thread
(see <http://forums.macworld.com/thread/100654?start=0&tstart=0>). Essentially (if it's correct), when selecting a UPS, one can't simply go by the power ratings in the specs of our
Macs (they end up "understating" (in effect) the size of the UPS you will need). More of a concern, however, is the possibility that the Intel Macs may be a bit "too quick" for any of the
"standard" UPS models (i.e., those based on the lower-cost, offline-technology designs, usually employed by UPS manufacturers for the home-computer/small-office market),
and require one of the "premium" models (i.e., those based on the higher-cost—often,
significantly higher-cost—line-interactive or online technologies).
Has anyone had any experience that would support or refute this?

Answer 1

You all seem to be calling upon your previous experience with APC products. And while I agree that experience is a great teacher, I’m not so sure how much of the experience you are relating is really relevant (i.e., the use of APC UPSs with recent-vintage Intel Macs). Quite frankly, I’m also not sure whether enough time has elapsed for the alleged issues raised by the APC tech to actually become issues for a lot of Mac users.
So, was the tech “full of it,” and simply trying to “sell” the APC customer—who had contacted APC for tech support regarding his 3-month old UPS—or was the tech honestly trying to help the customer? And if the latter, did he know what he was talking about?
My own experience with APC (limited as it is) combined with what I’ve seen and heard other folks say about the company, and the company’s overall reputation in the marketplace suggest that the tech probably was not trying to get the customer to needlessly buy a more-expensive unit. That leaves us with the question: Did he know what he was talking about?
The tech made 2 specific clams: One relating to power requirements, the other to transfer-time requirements. Everyone here seems to be focusing on power requirements, so let’s try to pass judgment on that first.
_Power Requirements_. The tech made the following statement:
+Apple uses Power Factor Corrected power supplies in their computers. When we+
+size a UPS for a computer with a Power Factor Corrected power supply, we+
+multiply the watts by 1.25. So, for the purposes of choosing a UPS for your+
+Mac, we would use a wattage of 280W x 1.25 = 350W. This would exceed the+
+watt capacity of the BE550R which can handle a load of 330W. I will place a+
+link here to a document that describes Power Factor Corrected power+
supplies.
He then provided the following link to a document located in the APC Knowledge Base:
<http://nam-en.apc.com/cgi-bin/namen.cfg/php/enduser/std_adp.php?p_faqid=8883&p_created=1193079387&p_sid=JU8cSF2j& p_accessibility=0&p_lva=&p_sp=cF9zcmNoPTEmcF9zb3J0X2J5PSZwX2dyaWRzb3J0PSZwX3Jvd1 9jbnQ9NCZwX3Byb2RzPTAmcF9jYXRzPSZwX3B2PSZwX2N2PSZwX3NlYXJjaF90eXBlPWFuc3dlcnMuc2 VhcmNoX25sJnBfcGFnZT0xJnBfc2VhcmNoX3RleHQ9cGZj&p_li=&ptopview=1>.
The document certainly seems to be “authoritative” in its discussion of “power factor corrected” power supplies and the Government’s updated Energy Star requirement (Energy Star 4.0, which took effect in July 2007—see <http://www.energystar.gov/ia/partners/fed_agencies/estar40.pdf>) that such power supplies be used in computers (e.g., desktops, notebooks, workstations, game consoles, and servers). So unless the document is wrong, or unless the tech is wrong about Apple’s compliance with Energy Star 4.0, it appears that the tech’s statement regarding the BE550R’s ability to handle the potential load of the customer’s post-July 2007 24” iMac is correct.
_Transfer-Time Requirements_. The tech claimed that Intel Macs require a transfer time of 4-5 milliseconds but that the APC Back-UPS series (which includes the BE550R) has transfer rates of 8-10 milliseconds. He indicated that this mismatch may very well have been a contributing factor to the sudden spurt of daily shutdowns that the customer had experienced. He put it this way:
+However, there is another consideration. Macs are more sensitive to power+
+fluctuations than comparably sized PC's are. My assumption, based on the+
+information provided, is that the BE550R may have been having very brief+
+transfers to battery caused by harmonic distortion in the input power. This+
+type of distortion is common and is not normally a problem. But, when your+
+UPS transferred to battery, one of two things probably occurred. Either the+
+overload issue caused your Mac to shutdown or the transfer time from on-line+
+to battery caused the Mac to shutdown. The BE550R, being a Back-UPS ES, has+
+a transfer time of around 8 - 10 milliseconds. The BR units have a transfer+
+time of 4 - 5 milliseconds. We have noticed that Macs need a quicker+
+transfer time than this. For this reason, we now recommend a Smart-UPS for+
+all Macs. Our UPS configurator is being updated to reflect this+
+recommendation. A Smart-UPS has a transfer time of 2 - 4 milliseconds which+
+works well with Macs. So, to make a long story short, we would recommend an+
+SUA750 for your Mac.+
He was clearly somewhat more tentative about this transfer-time requirement than he was about the power requirement. And I have yet to see any changes made to the APC website to reflect these new “requirements.” Nevertheless, his presentation seems “reasonable,” and certainly doesn’t come across as a “sales job.” From a user perspective, I just hope it’s a matter of a thoughtful tech pointing to a technically possible issue that may never be of real practical concern.