I have a 12-minute clip that I’m speeding up to fit into 30-60 seconds. That’s all I’m doing. It’s taking this long every time I want to try a different time value.
Tip: When editing HD video, plan for it to take a while.
(Interestingly, it’s barely touching the CPUs — it’s just slamming the hard drives. This is on a 2-disk RAID-0 array of 1TB WD Caviar Black drives, the fastest 7200 RPM hard drives available today.)