New Sata 3.0 GB HD on older MB?
Can I use a new Sata 3.0 GB HD on an older Motherboard that has a Sata II 1.5 GB connection?
Yes you should. Though sometimes, a drive does not get recognised and you need to put a jumper on the SATA drive so that it functions in SATA I or 150MB/s mode only.
SATA I = 1.5Gbps or 150MB/s
SATA II = 3.0Gbps or 300MB/s
If it claims it does SATA II and only supports 1,5Gbps operation, its lying and taken advantage of the fact that the SATA name was not trademarked or required certification from the SATA-SIG. Anyway, consider it a SATA 1 controller.