X8DTU-LN4F+ has the problem when I use AOC-L2208-H8iR this card in PCI-E slot. The problem is on the drive dropped while performing "dd if=/dev/sda of=/dev/null" for testing HDDs under RHEL and CentOS 6.2/6.3
Please disabled ASPM under RHEL/CentOS 6.2/6.3 version by using pcie_aspm=off command. This is the same report from FAQ#16225 posted in Supermicro FAQ portal.