Thank you for your reply. I have indeed tried all of the ports in all sorts of combinations and the ony one which worked was with both SATA SSDs plugged into the blue 6GB ports. I have tried swapping the SATA cables but to no avail. The systems is working fine but I still have this strange problem where all four of my SATA devices appear OK in the boot page of the BIOS: http://goo.gl/vIwxJ but on the configuration page, both SDs are missing! http://goo.gl/eDiHc
I have not tried a different power supply, how might this make a difference?
Thanks in anticipation.