ACHI - worth it over IDE mode?

[Legend]

Is ACHI worth doing over IDE mode? Or are they essentially one and the same when it comes down to it. I'm talking for a pretty straightforward setup, no RAID, just a Raptor and a couple of SATA drives.

 

[hardc0re_tid]

when changing from ide to achi mode on my p5b mobo, the system wouldnt boot, dont know why though. wil achi mode improve performance?