JMTH I just wanted to say thanks HEAPS for taking all that time & effort to post this & update us, even as I post this after all that time you started this thread. You have truly saved us A LOT of time trying to figure it all out.
I've always had my Thunderbolt 3 card that came with my ASUS X99 Deluxe II plugged in but never had any TB devices to actually try it until now as I have bought an Audio Device. I always wondered why it wasn't even showing in my Device Manager but just assumed I needed something plugged into my TB card to see it in Device Manager but ofcourse this wasn't the case. It was simply plugged in & not even in a working state that whole time.
Instead of even TRYING to bother getting my ASUS TB card to work smoothly, I decided to take one of your recommendations & buying a GigaByte Alpine Ridge Thunderbolt 3 card & I'm so thankful you did. Installed it in, double checked BIOS settings, downloaded latest drivers from Gigabyte & done!
Two Thunderbolt 3 ports working nicely & it's showing in Device Manager & my taskbar finally! ASUS is usually excellent quality in my many years of experience buying from them but that Thunderbolt 3 card is a big let down & troublesome.
Now I find out I can only expect the full TB 3 speed of 40/gbps if my cable doesn't exceed the 50cm's limit! That's just too short for me & my setup, so I have 2 choices if I want the full 40/gbps speed. Either buy an Apple "80cm" TB 3 cable which is the only passive cable I found over the 50cm limit which still provides the full 40/gbps speed, or buy an Active TB 3 cable which can provide the full 40/gbps speed at 2 meters.
Apparently the only catch with the Active TB 3 cables is that they can ONLY be used with TB 3 devices & not for normal USB-C 3.1 which doesn't bother me.\
Anyways just thought I'd also post this little info here for anyone actually wanting the full TB 3 40/gbps speeds.
Again JMTH we REALLY appreciate your informative posts & lovin my Gigabye Alpine Ridge. THANK YOU!