Which is FASTER - IRRT or AHCI - Using SSD?

I just got a new E6410 and installed a new Intel 160GB MLC SSD (Gen 2) in it...once Windows 7 was installed, configured etc I THEN noticed the system was set to IRRT for the SATA connection/mode rather than AHCI.

Searching around online I see that IRRT is essentially AHCI with added mirroring support for Intels rapid restore technology, (IRRT) but in what I've seen there has been some mention of those added features possibly adding overhead, latency etc.

I have no need for the Intel rapid restore technology but I do want to make sure this system/drive combination is configured to run as fast as possible but I can't seem to find a definitive answer as to whether AHCI is actually faster than IRRT or if there's no difference at all.

Which is faster? And why?

Any/all input is greatly appreciated!

Scott