I just tested it on my Indigo² with High-AA Impact+TRAM and it ran perfect and smooth. Also the bugs seen on vPro are not there. I will do a video about it tomorrow.
I just stumbled across Xash3D, an open source reimplementation of the Gold Source egnine known from Half Life 1. It would be really cool to be aple to play this on my SGI machines. Would it be possible to port this to IRIX?