quote:
32-bit mode with respect to IDE refers to transfers that occur over the PCI bus to the host system memory. PATA is limited to reading 16-bit chunks of data at a time from a drive. If you enable 32-bit mode, the controller will be set to temporarily store the data from one read until the data is available from the next read before mastering a transfer over PCI. So it can collapse two transactions on the IDE side of the controller to one transaction on the PCI side of the controller.

SATA doesn’t require a mode like this. It could be said that it’s always running in 32-bit mode, I guess — basically SATA transfers data in serialized packets across the interface to the drive and the controller will just buffer the data until it has enough to send across the PCI bus. There is no need to enable this specifically with a SATA controller.

source: http://hardforum.com/showthread.php?t=1287459

Quote:
Hey guys, according to everything that i can research about the whole 32-bit setting in some bios’s, its kinda a joke because the whole sata channel is a 16×2 stepping transfer, when you turn on the 32 bit transfer it in a way simulates 32 bit, and as someone said, once you get to you OS of choice it takes over.

As a little info to people who dont know, you can go under device manager in the control panel, and pull up the device SATA or depending on how old your machine is, IDE controller and check to make sure that your system is designating your drive to the correct UDMA, since this is what system xp uses to regulate disk access(hence, why it doesnt matter if you tag 32 bit or not). UDMA scales between 1-6(Im fairly sure theres no 0 :> ) and if you are running a sata drive with 3.0 it should be UDMA 6.

The only reason i gave the beginner course in device management is because i have seen a lot of new computers hear lately where xp picked PIO mode, dont know the official reason why, but it seems to happen on newer drives more than mid range drives, in my experience.

Also, even though i have heard from multiple sources it doesnt matter, I always bind my IDE and SATA controllers, mostly because xp associates them as one, and once less process to get to what it needs microscopically must make a difference.

source: http://www.tomshardware.co.uk/forum/149914-12-enable-transfer-bios-setting