Thanks, Kappy. Are you using Dragon Dictate in OS X or Dragon Naturally Speaking in Windows? No extra memory added?
You'd have to refer to the linked post to see the details, but you did essentially answer my question. It's nice to have some reassurance that an i7 processor isn't necessary. Hearing about being able to use an earlier generation is a bonus. A lot of us are always looking for ways to do Mac "affordably" and that information has got to make more than a few people smile.
I've used Dictate for the Mac on systems with 4 GBs of RAM. In fact I've used earlier products from MacSpeech (before they shifted to Dictate) all of which worked well on even earlier Mac models. I don't think you need worry about whether you have adequate hardware.
I don't use Dictate for personal reasons - not really necessary for me - but I have installed and tested it and all of the MacSpeech speech recognition products from when they were first starting up. They are helpful and reliable people to work with.