Reason for doing the bios hack is to gain speed in raid. But also for being able to use more then 2 drivers on the promise controller.
What is the difference between Lite and Full RAID?
The LITE BIOS are limited to a very restricted RAID implementation as follows:
? Max of 2 Drives
? Fixed stripe size of 64KBytes
? No support for Span mode
With Full RAID you can have:
? Max of 4 Drives (maybe 8?)
? Manual selection of the stripe size
? Support for Stripe, Mirror, Stripe + Mirror and Span!
TweakHardware