Possibly interested in a used quad core (not 2 duel core) or 8 core Mac Pro. I'm wondering: When did the 2.8 Ghz models first come out? How much RAM could the first ones handle? I called Apple tech support and they said January 2008, and 32 GB of RAM. I thought there was a time when the 4 and 8 core Mac Pros could only take only 16 GB of RAM, so I don't know how much of their info was correct. Thanks.