1070 ti pulling 480 sol/s isn't pushing hard at all.
70C though is high on temp for 115 watts, especially with 80% fan - SOMETHING is blocking airflow to the cards or the room is VERY VERY hot.
Those Aero blower cards shouldn't have THAT bad of cooling, though they would tend to run a LITTLE warmer than good fan-cooled cards unless they're in a case.
My EVGA and Zotac 1070 ti cards in my "new shelf/rack" first rig only run 62-63C at 50% fan in a room that is 86 F measured right above the "room fan" that blows air into that rig.
It's POSSIBLE that you got a batch of flaky cards - but if they're working for video playing it sounds more like you're pushing them too hard, probably on the memory clock.
What are your settings if you don't mind asking? I think the main problem is on the USB stick, and it was the reason that system crashed and not the OC speeds. Even if for sure i was pushing the MC way over what needed.
Do you recommend anything to remote monitor the rig using nvOC? I think i will end up using teamviwer but was looking for other alternatives