9 Replies Latest reply on Oct 19, 2011 5:54 PM by illucine


    illucine Level 1

      I'm getting close to installing software on my new hardware build (first time for me) and am wondering whether to enable AHCI before installing Windows 7.  I've seen some comments about incompatibility problems but most of those appear to be about 5 years old when AHCI was newer.  I'm running on a Sabertooth X58 and would like to know if there is any reason not to change the default IDE mode to AHCI on both the Intel (SATA 2) and Marvel (SATA 3) controllers?



        • 1. Re: AHCI
          Harm Millaard Level 7

          I can't explain why, but turning it on caused me serious headaches so I left it off.

          • 2. Re: AHCI
            RjL190365 Level 4

            I suspect that your problems with onboard AHCI is due to the conflict with the discrete hardware RAID. The discrete RAID card is already running in AHCI mode, but enabling AHCI on the onboard Intel SATA controller seriously degrades performance of the discrete RAID card by misusing the CPU and system RAM. No wonder why some of the systems with discrete RAID controller cards underperform (based on their results posted on the PPBM5 results list). Thus, when using a discrete RAID card, be sure to set the SATA mode on the onboard Intel SATA controller to "IDE".


            On the other hand, if one is using the onboard Intel RAID controller in (R)AID 0, the AHCI cannot be disabled because selecting the mode to RAID on the onboard Intel controller automatically enables AHCI.

            • 3. Re: AHCI
              Jim_Simon Level 9

              I turn it on myself.  AHCI offers better performance with SATA drives than IDE mode.

              • 4. Re: AHCI
                illucine Level 1

                Sounds like a toss up - maybe I should just try it and see if I encounter problems.

                Harm, what sort of "serious headaches" did you encounter - random BSOD type stuff?

                RjL190365, what do you mean by the onboard Intel controller "misusing the CPU and system RAM"?

                I'll probably set up 2 pairs of RAID 0 later, but wanted to shake things out with discrete drives before I throw in another variable like RAID.


                A bigger maybe, farther down the road, is the possible addition of a discrete RAID card to my system.  It seems like I've heard of people running RAID 0 off the onboard controller in the same system with another controller card (running RAID 3, for example), but it sounds like you're saying that would degrade performance.  So, if I wanted to setup multiple RAIDs with a discrete controller card, then would it be best to run them all off the discrete card?

                • 5. Re: AHCI
                  RjL190365 Level 4

                  What I meant by "misusing the CPU and system RAM" is that AHCI on the Intel controller requires software - and AHCI behaves the same as software RAID (since the onboard Intel SATA controller is not a true hardware RAID controller, but rather a software-controlled one).

                  • 6. Re: AHCI
                    Scott Chichelli Level 3

                    ACHI is required if there is a raid mode as well thats the best pick but IDE mode is a no no..

                    • 7. Re: AHCI
                      RjL190365 Level 4

                      By the way, "RAID 30" is not what you think it is (RAID 0 on the onboard Intel controller and RAID 3 on a discrete Areca RAID card) - but it actually is both RAID 3 and RAID 0 on the same Areca controller with the same array (in Harm's case, each set of six drives are in RAID 3 with one of the six drives in each set dedicated to parity, and then the two sets of six are then striped together in RAID 0 on that same Areca controller). And the two major reasons why Harm opted not to enable AHCI on the Intel controller are that he is using a discrete hardware RAID controller in his system, and that software motherboard RAID (that includes chipset AHCI supprt, which uses exactly the same driver as the software Intel RAID) does not play nice with discrete hardware RAID.

                      • 8. Re: AHCI
                        Harm Millaard Level 7



                        Very well worded. Thank you for giving this answer, because I had a major (external) internet problem all day (the ISP went down), which is now luckily solved.

                        • 9. Re: AHCI
                          illucine Level 1

                          Who said anything about RAID 30?  FWIW, I thought RAID 30 is exactly as you describe it.  What I'm wondering about is setting up multiple RAIDs.  For example, having source media on a RAID 3 and caching on a RAID 0 (two separate logical volumes, e.g. D: and E:).