missed my 'reply to all' button, here goes the 2nd try.

So 'passthrough' means that the controller lets the OS see the physical disks just as they are, but with an invisible cache in between that buffers operations. This way there is no advantage of the onboard XOR engine, but you do profit from the intelligent cache, which is the most important anyway imho. JBOD mode is at a disadvantage because in this mode the OS sees one large drive, and is not able to stripe the data to multiple disks, not taking advantage of the fact that you have multple spindles available. Makes sense to me :). I must admit, I do like these results. Very promising.

Further tests would be using an SSD for the ZIL, testing linux and NT, etc. But let's not go there ;).