How exactly do utilities like Teracopy implement high-performance copying? In other words, what are the performance bottlenecks in explorer.exe? Personally, I've observed that:

1. Explorer attempts to do a file enumeration prior to copying, which sometimes could waste a lot of time.

2. It seems tools like Teracopy use buffering aggressively, which can speed up the copying significantly based on my experience on Windows XP with slow HDDs.

Are there any other points worth noting?