Thanks, Al, more good insights and I appreciate it. I’ve pretty much decided against the 08 tower purchase, because of several observations, here and in the Apple forums, about its limitations. It does have 24GB Ram already installed, but that doesn’t balance out the other drawbacks in my mind.
I like the portability, but am ambivalent about using the laptop too heavily for video production. For now though I’ll likely put in an SSD system disk as well as an external media TB RAID. Maybe an external scratch as well via TB. Both good investments whether or not I eventually add an iMac or a newer tower. That should help the export times considerably; my HDD is only 5400, and the single external 7200 disk was connected via usb3 – which, from my experience is great for transfer, but not so much for media production reading/writing.
My slowdowns probably are related to an inferior (for video editing) disk setup, and the fact that I’m editing Nikon’s D600 h264 rather than avchd. The Premiere exports have been straightforward, one video track with two audio, though with some color correction sharpening effects. And I’m new to this… took me a bit to discover that I didn’t have the CUDA driver installed. That helped some on renders, but didn’t see much change on the export. More to discover, I’m sure.
What processor are you running in your iMac? I’d consider that route if I could get an i7 for less. Maybe the next time they get updated, though I’d like to run a separate system/startup disk, and I don’t think I can do that in the iMac?
Thanks again, helped a lot. Here’s additional feedback on the Apple forum: https://discussions.apple.com/message/25622848?ac_cid=op123456#25622848