The 'TH' version is a bit different. It supports faster ram, up to ddr4 3800 while the regular ud5 supports up to ddr4 3466. The regular ud5 has dual lan's that can be teamed, the TH doesn't. The reason for the TH designation, it supports thunderbolt and the regular ud5 doesn't. There are some other minor differences like oc and eco buttons, varying usb ports and sata ports (likely due to the tradeoff of supporting thunderbolt).
The 'TH' version is a bit different. It supports faster ram, up to ddr4 3800 while the regular ud5 supports up to ddr4 3466. The regular ud5 has dual lan's that can be teamed, the TH doesn't. The reason for the TH designation, it supports thunderbolt and the regular ud5 doesn't. There are some other minor differences like oc and eco buttons, varying usb ports and sata ports (likely due to the tradeoff of supporting thunderbolt).