What type of interface should give the lowest CPU load per track ?
Firewire, USB, USB2 ?
Core audio or VST etc ?

One thing to note, on my old PC, if the CPU(3Ghz P4) approached 80% the audio would crack up regardless of interface or application.
But my powerbook continues to provide pretty much crackle-less audio when the CPU load 99-100%...weird or what !
Threlly
www.joyfulprocess.com

Since I just read up about and use this stuff and have no tech savvy beyond reading and talking to tech guys, don't take this as absolute fact.

Any of the busses you mention (Firewire, USB, USB2) should be low usage on the CPU if the drivers for the interface are written well. Bandwidth is more of a problem, but if you're recording two or four 44.1/24 tracks at a time it wouldn't be an issue in any format. Firewire interfaces, while more expensive, have the best I/O bandwidth performance, but only you can determine whether you need it.

Core Audio and VST are actually two different things in OS X. Everything runs through Core Audio. Steinberg has opted to stay with its plug-in format, which is VST. If you're asking whether an app like Logic (which is built to fully utilize AU plugs and Core Audio) will run more tracks than Cubase SX (which uses VST plugs and Core Audio), my guess is that Logic will win. I use SX and it's a CPU hog, but, overall, I'm pretty happy with it.

On my PowerBook, though, I run Digital Performer (no dongle needed like SX). If I were buying DAW software now for my laptop, I'd probably go for Logic since it's got a little more going for than DP. Quite frankly, you can do great work in all 3 programs. As the old addage goes, it's the craftsman, not his tools...

Jeff

Hi,
Yep, I'd heard the reports about VST, but I thought the VST audio drivers where a seperate sub-system to core-audio, mainly because I have used VST installed audio for other apps even when Cubase was not running.
So far though, the core drivers are doing the trick, they seem to halve the CPU load on Reason when running the firewire 410 compared to the built in sound card, not that its been a problem though.
Well having played with most of the currently available DAW apps I've settled on......Garageband.
I can hear the groans from here, but from my point of view, it's dog-simple to use, reliable, and for home composition and basic vocal recording it works spiffingly with Reason.
Gary