A Precision Tower 5810 user reported that when they received their system, the Thunderbolt 2.0 card was not recognized by the Thunderbolt application and that the card did not function to its full capability.
It was determined that the card was installed in the PCIe 3.0 slot (SLOT 1). The Thunderbolt 2.0 card setup guide indicates that for proper operation the card must be installed into the PCIe 2.0 slot (SLOT 5) (Figure 1):
Figure 1: Installing the Thunderbolt 2.0 add-in card in Slot 5
The Thunderbolt Add-In-Cards Setup Guide indicates that this card should be in PCIe slot 5 for both the Precision Tower 5810 and 7810. For the Precision Tower 3620, the Thunderbolt 2.0 card should be installed in slot 3 for it to function properly.
If you encounter this issue, ensure that the Thunderbolt 2.0 card is installed in the correct PCIe slot.
Once the Thunderbolt controller card was installed into the correct PCIe slot, the card was correctly identified by the Thunderbolt application and functioned normally.