these cards - unlike its predecessors - have double ball bearing fans
Odd, I've never seen a Gigabyte card that didn't use a dual ball-bearing fan, though I concede I've only owned a few of their models.
My Gigabyte 1070s ARE dual ball-bearing - both the full-length 2-fan cards and the single-fan "ITX" models.
Gigabyte GTX 1070 G1 Gaming (GV-N1070G1 GAMING-8GD)
Gigabyte GTX 970 OC (GV-N970WF3OC-4GD)
Gigabyte GTX 970 mini (GV-N970IXOC-4GD)
Gigabyte GTX 750 Ti Windforce OC (GV-N75TOC-2GI)
Gigabyte GTX 780 Ti (GV-N78TOC-3GD)
These are the cards I had and ALL have crappy sleeve bearings. And they got progressively worse (except for the 780 Ti) with each iteration until AORUS came along with its superb fan design.
You can tell if a GPU has crappy sleeve bearing fans by: just touching/moving them and they feel like a plastic toy from a Kinder Surprise, seeing the product pages (ball bearings are always a heavily advertised feature) or by just watching them spin slower and slower after months.
Edit:
GeForce® GTX 1070 Xtreme Gaming 8G (rev. 1.0) - GV-N1070XTREME-8GD
GeForce® GTX 1070 Xtreme Gaming 8G (rev. 2.0) - GV-N1070XTREME-8GD
AORUS GeForce® GTX 1070 8G - GV-N1070AORUS-8GD
Only these 3-fan Gigabyte 1070s have double ball bearing, every other one has sleeve bearing.