The latest installment with speed improvements: sprites, thread tweakability, and Windows GDI driver fixed (often faster than ddraw). EDIT: just replaced it with even faster sprites thanks to http://forums.inside3d.com/viewtopic.php?t=5268
A new handy feature is the diagnostic report. Look for S8report.txt in the /Quake/super8 folder. The report includes very basic OS and CPU information, and a list of cvars which are different than default values.