I have an ASUS M4N78 Pro MB (which has the NVIDIA GeForce 8300 chipset).
I am currently using two of the six SATA connections for my hard disk (500 GB w/Win XP - boot device) and my DVD drive.
Windows XP was installed with the MB in SATA mode (not AHCI or RAID -- I think "SATA" here means IDE emulation).
Now, what I would like to do is add the capability for a couple eSATA-connected external drives (I'm looking for high bandwidth or I would settle for USB 2.0). I want hotplugging capability for these drives, so I think I need AHCI.
I'd like advice on what the best path is to achieve this. Here are the options I know of:
A. Extend two of the four free internal SATA connectors to a slot plate with eSATA connectors. I know this requires using the "F6 + floppy" method to get the AHCI/RAID drivers on the WinXP drive. Can this be done without re-installing WinXP? I know I need an old-school floppy drive for this... I'm looking into that right now.
B. Install a two-port eSATA card. Does this also require setting up the MB for AHCI or RAID, or do I get around that by using the card? Also, I don't have the PCIe x16 slot available for use; only PCI and PCIe x1. Not sure if that aces me out of this option.
If you want to be sure you do have full eSATA functions, you are best to buy and install an eSATA port card in the PCI slots. (The PCIe x1 slot would be good). This card very likely will have a driver CD with it that you will have to install. I fully expect that it will include the AHCI device driver you need for using eSATA devices. You would NOT need to change the way you have set your internal SATA ports.
Many people are successful in using simple adapter cables with back plates to adapt internal SATA ports for use by an external eSATA device. For the most part these work because, without being clear about it, the mobo makers and their BIOS chips actually implement the required eSATA features in the plain SATA ports. The problem is that you can't know for sure whether this has been done in your system. The two most important features of eSATA that are not in the original internal SATA specs are support for longer data cables (using higher signal voltages) and Hot Swapping support. If you NEVER indulge in Hot Swapping with your external eSATA device, you may never need the latter feature. So this simple adapter plate technique can work for you, as long as you understand there is a small risk.
To use an adapter plate and connect your eSATA device to an internal SATA port, you CAN do it without a lot of trouble. Look in your mobo manual, page 2-11, Section 2.3.7. It says that, if you have configured your ports as SATA, only the first four of your six ports are usable and will be detected automatically. BUT you CAN use the last two ports (5 and 6) in AHCI mode if you simply install the AHCI driver in your OS, which is Win XP. Then these two ports only will operate in AHCI mode, while the first four continue to operate in SATA mode with NO change in your BIOS setting. So you can use those last two ports to "convert" to eSATA use.
Now, how do you install the AHCI driver? You do NOT have to have a floppy drive, and you do NOT have to re-install Win XP and use the F6 technique. That process is only required if you plan to have XP BOOT from an AHCI device. You don't need that. What you can do, though, is to find and install the AHCI device driver in Win XP when it is running, just as you might for any other new device like an internal modem card. The driver probably is already on the CD that came with your mobo. Once that is done, Win XP will continue to boot from and use the SATA drive(s) you have, but will also have the ability to use any AHCI device connected to ports 5 or 6 - because it will find and load the AHCI driver from the hard disk it just booted from.