Well, Audyssey makes a dozen or more technologies or something like that, right? Ok, with the MultEQ techs, there are at least a few existing versions. I've already explained to you why the 40.1 would not be a consideration for me since that version of MultEQ is two generations old. Or am I mistaken? I did, right? It was you, right?
I've timed myself at half an hour way back when (I want to say something like 35 min), with 8 channels (7.1). This was timed from when everything is turned on, with the mic plugged in.
I would assume there will be variations depending on the number of channels (hey 9.1 DSX is about twice the channels of 5.1, and forget 11.1), the processing power available in the specific model, how efficient the user is with the process, and of course whether it is 1) 2EQ, 2) MultEQ, 3) MultEQ XT, or 4) MultEQ XT32.
Anyways for one anecdotal data point, my Onkyo 805, using MultEQ XT, with three DSP chips (don't know how many of those are dedicated to Audyssey), using a mic boom/stand/adapter, took about 35 min. So my guess is that I could do a 5.1 system in less than 30 min. How much faster could ARC or any other similar EQ be, without giving up significant resolution (or perhaps extra costs towards super fast processors)? The end calculation does take quite a while.