Try running it with only one stick of ram at a time.
Thanks for the suggestion Mad Mac - I'll try it. I'm curious though, is it the error code that makes you think it's a RAM issue?Try running it with only one stick of ram at a time.
I stumbled upon your original thread at <http://forums.macworld.com/message/643752> while researching UPS requirements for my new 24" iMac. I had just purchased the APC BE550G, and was rather upset to read what the APC tech had told you. Based on that "advice," I "upgraded" the BE550G to the BE750G, hoping that the tech's assessment may have been correct regarding the power requirements, but incorrect regarding the transfer-time requirements.My new Intel iMac worked for 3-4 months just fine and then started exhibiting symptoms just as you describe. I finally traced the problem to the (new) UPS I purchased along with the iMac. I have an APC Back-UPS BE550R. I discussed the problem with APC tech support and they researched the issue and determined that the new Intel iMacs probably need the Smart UPS series because Intel Macs require a transfer time of 4-5 milliseconds but the Back-UPS series has transfer rates of 8-10 milliseconds. Be advised that the Smart UPS series is quite a lot more expensive than the Back-UPS series.
For the record, he said that my 2.8 GHz 24" Intel iMac has a maximum wattage rating of 280W and he concludes that I need a UPS having at least 350W capacity due to start-up surges. I calculated that my iMac would run for 9.5 minutes on the recommended smart UPS SUA750 ($320) in the event of a power outage. I haven't purchased a new UPS yet as I'm hoping to get feedback from others whether or not this makes sense.
Meanwhile, my Intel iMac has been plugged into the wall socket for a month now and I haven't experienced any further problems.
Hmmm...I don't see any change to the configurator. It still refers only to G3, G4, and G5 iMacs only.I waited until this week to see if other people on several forums would provide some knowledgeable information, but nothing much developed. I noticed that APC's web site has been updated to at least include Intel iMacs, but as you said they don't recommend the more expensive smart UPS's but rather the Back-UPS series.
The folks responding to my Apple Discussions thread have been rather vocal in their opinions that the APC tech is absolutely wrong.So I emailed their tech support once again and received the reply to go with the smart UPS rather than what their web site says.
Spending $320 for a UPS to keep an $1,800 machine online for a few minutes during an occasional power outage is a bit too rich for my blood. Perhaps I’d feel differently if I lived in an area where power outages/brownouts/fluctuations were more of a problem. (One of the folks who posted to the Apple Discussions thread pointed me to a site (<http://www.excessups.com/>) that offers lower-cost, refurbished APC UPSs. But I’m not enthusiastic about used electronic equipment from strangers.) But even if I lived in the middle of the Florida Keys, I doubt that I’d ever consider the SUA 1000 or 1500—not for a single iMac!In fact, they said that either the SUA 1000 or SUA 1500 would be safer than their original recommendation of SUA 750. Those two are way too expensive to use on an iMac so I ordered the SUA 750 yesterday but haven't received it yet.
Well, I’m awaiting a response from the APC tech folks regarding their diagnosis.I have never had the problem with the UPS you mention when the iMac is off, but I rarely turn it off.
Still waiting for it to arrive?... I ordered the SUA 750 yesterday but haven't received it yet.