As per question.. esp curious about Saffire Pro.

Obviously you will be in Dongle Hell, and of course there is no performance benefit. I'm looking at laptops with Thunderbolt 3 built in but also curious about desktops.

Anyway please tell us your setup if successful.

I assume not then!

Don't take it personally Alex :)   I just think everyone has gone elsewhere. This sub forum is a ghost town.
If your brave ask on Gear Slutz or Studio one forums. 

I've seen a thread like this elsewhere and the suggestion was to look on the Mac side.

Thanks.
I'm talking about PC motherboards (or PC laptops) with built in thunderbolt 3 (not Macs) connecting FireWire audio interfaces via dongles. I know it should work in theory.

If anybody is actually running a setup as per OP (and happens to be here :) ) please share your real world experiences and specs. Thx.

I think that Jim Roseberry posted a detailed answer to another question like this last year.
 
Recall that it was possible, but with a few additional requirements.

Yes it's definitely possible with one or two dongles.

I'm asking comments from people who have done it, what are their real experiences (is it solid?) and what their specs are.

Up until few weeks ago I was still using a Presonus fp10 with FireWire, I made the move to a PreSonus Quantum which is thunderbolt 2, turns out it was nearly impossible to make that work and the cards themselves were about as expensive as just upgrading my computer (which I did), now I installed a new motherboard and use my quantum 2 thunderbolt 2 interface with an adapter to my USB-c/thunderbolt 3 port. I know this doesn’t directly answer your question, but just kind a similar situation I encountered.

So don't those PCIe FW addon cards work anymore?

Please refer to OP.