Per Dell-Cares: The system is capable of supporting it but as per the current configuration it's not shipped with it. Also, regarding the TB3 header, you can contact our sales team for more information. 1-866-440-33557am - 12am CST Monday - Friday As per the manual below, there is native TB3 support on the system as there is a slot front panel.Precision 3440 Small Form Factor Setup and specifications guide
I ordered this machine before xmas. I just noticed that the website gives the customization option to add "PCIE Thunderbolt 3 Card (Low Profile) [555-BFWU] / G7F13PO".  Does it mean the motherboard already supports TB3? I am hoping to add a TB3 port to be able to use my eGPU box when needed. However, I can only find this part #555-beoz on dell website (which says compatible with the old 3420 SFF only). Dell Thunderbolt 3 PCIe card - 2 Type C Ports, 1 DP in Low Profile | Dell Canada Also, I understand I need a TB3 header on the motherboard to be able to use TB3. It does not appear 3440 SFF motherboard has a TB3 header similar to this on 3420 Dell Precision Tower 3420 Owner's Manual | Dell Canada Your help is greatly appreciated.
Thunderbolt 3 support for Precision 3440 SFF?