We plan to purchase a PE2950 and build raid5 using 4x500G sata disks. If my recall is correct, one of the docs from Dell says the disk has to be SATA II to be installed in PE2950. The Seagate Barracuda ES disk ST3500630NS is prefered as it's server class with NCQ feature. According to http://www.seagate.com/www/en-us/products/servers/barracuda_es/, the interface speed of the series is 3Gb/s which is likely a SATA II, but it also specify it's SATA I interface. We are kind of confused and don't know if the Barracuda ES SATA disk is appropriate for PE2950. If not, what alternative we can use? Any suggestion will be appreciated.