I currently have a ASUS P5K-E/WIFI-AP running with Raid 1 boot drive using the onboard raid, raid 5 data on an adaptec 5805 in the bottom PCI-E slot, 7600GT in the main PCI-E slot. I use this system more or less as a storage server on the network.

Apparently this motherboard has 20 PCI-E lanes, 16 dedicated to the graphics slot and 4 shared between the bottom x16 slot and the two x1 slots.

The Adaptec 5805 is an 8 lane card according to Adaptec's website. I am assuming that it is working in the bottom slot with only 4 lanes.

I wanted to add a USB3 card in to make the backups faster. I put in a PCI-E x1 USB3 card and it prevents the Adaptec card from being seen by the motherboard. No adaptec raid display on boot up. I assume that the usb3 card takes one lane from the bottom slot dropping the raid card to 3 lanes.

So I moved the Adaptec to the main x16 slot and added a PCI graphics card. Now when the system boots, the onboard raid does not show up and of course no OS is found but the adaptec raid bios starts up and works fine.

Any ideas on how to get this system up and running with both the onboard raid and the adaptec raid card in the x16 slot?


Probably this move changed the order of the drives, so BIOS tries to boot not from RAID 1, but from the Adaptec card.

Boot to BIOS and look for options defining from which hard drives the system should boot. There may be also option to boot first from the built-in controller or from add-on controller. It may be a bit of trial and error, but shouldn't be harmful (you'll either boot off one of the RAID 1 disks, or the boot will simply fail).

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