27" 2011 iMac. I ordered a CP1000PFCLCD, and I'm waiting for such UPS to arrive. In the meantime, can I use this one I already have?: http://www.amazon.com/APC-Back-UPS-...1?ie=UTF8&s=electronics&qid=1305563490&sr=8-1 My guess is YES, since it supports 450W according to that page. Just need to use it for about 3 days.