They currently show up in device manager as "Intel(R) Ethernet 10G 4P X540/I350" (10G ports) and "Intel(R) Gigabit 4P X540/I350" (1G ports) with Dell OEM drivers, when trying to change the driver windows shows "X540-AT2" (10G ports) and "I350 Gigabit Network Connection" (1G ports) as a matching driver.
Hope this can help.