|Disadvanteges, too - but mainly|
Advantages of an O2 at 600MHz
It is fast. It is cool. It is low-power. It is silent.
Ever wanted a faster browser on an SGI Indigo machine?
Why not put a 600MHz O2 beside it (or in your basement),
and run applications remotely, i. e. the X11-style.
If you´re on a 100MBit Ethernet, you´ll find there´s no difference.
E. g. Mozilla Firefox, far too slow to be of any use on an old R4000 Indigo machine, slow even on a R10000@195 Indigo2, suddenly becomes a tool again for everyday use!
Firefox 1.5 on the O2@600MHz subjectively compares to it on an iMac equipped with a FastMac 550MHz G4 & 1GB RAM running MacOS X 10.4. Or on a 1.3GHz AMD & 1GB running Debian Linux.
Combined with the Toshiba DVD-ROM mod (that one is plain simple: get one, replace the original CDROM with it) 600MHz are pretty enough to even smoothly display DVDs on the O2 with mplayer.
There´s not much comfort implemented in mplayer, but hardware does not restrict it. Still no Xine port for IRIX, though. Sigh.
Last but not least:
a fully equipped 600MHz O2 consumes about 70 Watts.
That is again a tenth of what an Octane machine needs, and still much less than the consumption of an Indigo2 ...
Todays Intel based "Industry Standard" architecture will result in power consumption of about 250 - 350 Watts, even more - depending on which components are chosen.
There are AMD and Intel CPUs available which itself consume/dissipate as much as an entire SGI O2@600.