If you have an external box that holds multiple hard drives (like a Mediasonic HF2-SU2S2/HF2-SU3S2 or Sans Digital TR4M+BNC) and your computer only sees one hard drive when its hooked up via esata then this card will rectify the situation. Install the raid driver if you want raid 0/1/5. Install the base driver if you want to see all the disks independently. On a Win 7 box it pulled the base driver automatically from Microsoft.
I really wish this product came with a low-profile bracket I would order a few more if it did. Besides that gripe, it works flawlessly. I didn't need the driver CD that came in the box because Win 7 Pro 64-bit found the driver for me automatically.
I just wanted to state that it works fine in my PCI express x 1 slot. 2 of the earlier reviews claimed it had to go into a x4 slot, but the manual doesn't support that claim and it seems to run just fine in my box. I have Windows 7 and am using the drivers that came on the CD. I just popped it in and am getting a solid 80 MB/s transfer rate to my external SATA dock.
PROS: Cheap and seems to work just fine. I have it in a PCI-e x1 slot.
I was impressed when I purchased the adapters to upgrade my dell inspiron 530. I had only 4 sata ports and needed more. Yesterday (04 Sept 2011), my system locked and for the next 15 hours I removed everything and slowly reassembled my system. The culprit was my sata card. Now I'm back to only three drives and a cdrom. Not sure what I'll do.
PROS: Great price and performance
CONS: One of two failed after just fourteen months