By setting it to combo on the 9100, please note that you will be giving up 2 of your sata slots.... You will only be able to use SATA 0 and SATA 2 SATA 1 and SATA 3 will be disabled and cannot be enabled. If you change your Dimension 9100 Bios setting back to AHCI, your windows will not boot up. It will give your BSOD. Just an FYI.