Hello, After a lot of research and 3 weeks, I try to expose my problem on your forum, because some of you seems to be really pro Before I begin, my apologizes for my French's English, which is not very good, so I hope it will not be a problem... So : -Computer, Dell precision 690, 12 go Ram, 2 disk on Raid Mode, and 2 others disks plugged on the mother board. (so just 3 sata connectors left) -Esata brackets plugged on Esata 0 and 1 (2 of the 3 connectors left) -The older external disks, built with 500go internal disks and disks case with esata (about 2007 or 2006) -The new disks : Lacie Hard Disks Quadra 1To (2010) So my problem is with the new disks, not detected by the Bios when I connect them with the same Esata Bracket used for the older disks. In the Bios : the error messages, when I connect the Lacie's Hard Disks : "Lacie Hard Drive not found" and when I try a different setting in the Bios, with AHCI enabled : "AHCI bios not installed" + "Port 00, Device Verify Failed" + "Port 01, No device detected" I have to say that I tried AHCI, but I really don't know what is it, I just tried that because it seemed to be interessant But it doesn't work at all apparently... I didn't want to flash the Bios, or do an update, because I'm really not use to manipulate it, and I have only one computer to work... And I have to use it everyday for my Job... I also tried to test the Lacie's hard disks with Usb, they work perfectly. So it will be really unlucky to have the same esata problem on the two disks if they were defective. _____ After my tests, I contacted : Dell : reponse : Esata is not compatible with the motherboard... Me : ok but esata brackets with older disks worked perfectly... Bye. Lacie : Strange, it should work. Try on an other computer. Me : Thanks, I don't have any other computer. Bye. ______ So, I think, like Dell said, about a problem with the motherboard. But I think, with more precision : maybe the motherboard is ok with brackets Esata1 and disks in Esata1, but doesn't understand anything with Lacie's and Esata2 with esata1 brackets... maybe because too recent for the Dell precision motherboard. Maybe some of you begin to see the problem, and with some chance, a solution ___ I continue : I think about buying a PCI express Card 8x with esata2 connexions. So if I'm not to stupid, the moherboard should let all the work to the "Pci" Card...? And it should work ?? (when I spoke about this solution to Dell, reponse "no"... and to Lacie : "Don't Know") The Pci express 8x Card with Esata2 is about 300€/$. And I would like to be sure of this solution before buying it... And I choose Pci express 8x to have a good connexion to support the two Esata2 disks... Do you have a better answer than I heard from Dell or Lacie ? Is this solution is ok ? Or if you think about a "simple" update of the Bios without buying anything else... With, AHCI, or anything else, could you explain me the exact way to proceed... I really don't want to make an error and kill the motherboard... Thank you very much for your answers, I hope to find a solution, because it's too late now to send back the hard drives... Of course, if you need some other precisions, I will be glad to answer. Fred Ps : the motherboard of the dell precision in the attachment .