Render time will also depend on the grading itself. Primary only? Secondaries? How many? Vignettes? etc, etc. The more you use the longer it will take. Of course a faster machine will give you faster renders.
You should send a 10sec 2K clip to Color, do not grade and render it. That will give you the faster render time since there is no color grade at all. Then you could add a primary - render, then try a secondary - render and so on.
Those little tests will give you average times of rendering according to your machine and 2K media.
Check the New Apple Color - Training DVD!!!
www.callboxlive.com
Stuart Ferreyra
Timecode Multimedia
Owner / Colorist
www.timecodemultimedia.com