Windows 7: HDD's and Ultra DMA

HI all,

My question relates to Ultra DMA. On both my pc's my opticla drives are reported (in the device manager) as running in Ultra DMA Mode 4 as they should. Whereas on one of my pc's my HDD is at Ultra DMA Mode 6, which it should also, the other one is only running at Mode 5. One solution I've come across is that it could be because the HDD and the optical drive are sharing the same channel. (which is whats reported in the device mng)

How do I change the channel? Do I just to move the SATA connector to a different slot on the motherboard?

HDtune reports that the drive is capable of running in mode 6.

I am aware that the difference is negliable (or is it...), so its more to satisfy my curiosoty.

Cheers