Ze stránek Elcomsoftu, z roku 2008:

For RAR 2.0..2.8 archives, ARCHPR can try a few thousand passwords per second. RAR 2.9/3.x encryption is even better (see UnRAR sources for details)– recovery speed is extremely low, just a few passwords per second. So for such archives, brute-force attack is almost useless, and only dictionary attack is more or less effective.