Gigabyte vs Intel Sata Controllers

Reading the manual of my (yet to arrive) ga-p55m-ud2, I see sata ports (2) dedicated to a Gigabye controller, and other Sata dedicated to an Intel controller (7, I think).

The manual is quite specific how to enable either and use either set for raid, but nothing indicates the reason one would have two different controllers.

What's the point? Anyone know?

I plan to boot from a standalone drive, have a second standalone drive as a scratch storage, and finally have two additional drives in raid 1 for work storage.

Would there be any logic that would drive me to use one or the other controllers for the raid? or the boot?

Thanks in advance for any thoughts.

Best,
Bob

System in transit:
i7 860 on Gigabyte ga-p55m-ud2; 4x2 mb G.Skill ddr3-1600

Twoboxer is right - don't use your GSATAs (typically, jMicron JMBX36xx chips) until you've 'run out' of Intel ports; the Intels are 10% faster in normal use, 12-18% faster in RAID, the firmware is better, the automatic monotoring/repair software is infinitely better and more robust - an all-around better deal! The jMicrons are a good place to park a SATA DVD, if you're using one...