Here is a list of some things I found that may or may not be common knowledge. Please add your own discoveries.

When using the Auto Calibration your speakers are all set to small.

When you look in the manual for information on the front panel inputs it says se page "TK". No such page and I couldn't find front input info, not saying it is not there just couldn't find it.

There may be a few floating around in my old 990 review. Here's one that I didn't find out until I'd had the 990 for a while:

The "Upsample" mode can be used with Dolby Digital and DTS sources while preserving the multichannel signal, although the processing power required makes it impossible to overlay matrix processing modes like Pro Logic IIx.

Quick question Gonk, as a potential 990 purchaser, will the "Upsample" mode function with analog sources such as multi-channel DVD-A and SCAD fed through the 5.1 analog inputs?

I don't believe that the multichannel analog input allows any processing modes to be selected (including modes like "bypass" and "upsample"), although I'm not in front of my 990 to double-check that.