Seeing about 25% speedup here with just the Rails 3.2 RC1.

Combined with rspec-rails 2.8.0.rc2 (which includes some Rails 3.2-related changes), I saw my test suite go from ~2.5s (Rails 3.2.0.rc1 w/ rspec 2.7.x) to ~0.43s (Rails 3.2.0.rc1 w/ rspec 2.8.0.rc2).

Ruby 1.9.3p0 across the board.

Just upgrading to rspec 2.8 made my test suite run 10x faster. You might have David to thank for a lot of that speed up. :)

Certainly a LOT of it is rspec 2.8.

But there was a definite increase with Rails 2.3 as well. :)

I agree. 2.3 was much faster :-)

IMO, 6.6 seconds to boot the app is still too slow, but it's certainly progress. :)

Sure, but it's better than the 15 seconds on ruby 1.9.2 and rails 3. Things are getting better!