In the linked test, Supertech synthetic is not much faster than 100-per-cent dino at –20 C, reckoned extreme in warmer climes. This "cold"-pour test is recent: 2019.
Speaking of 2019, It hit –40 in Winnipeg on January 30 — not the wind-chill temperature, the real thing. Other days were nearly as cold. If Supertech is that sluggish at –20 C, imagine it at –40. I'll stick with plain-vanilla Mobil 1, the fastest cold pours in older videos, which, if I remember correctly, used 5W30, pre-dating my new favourite, 0W30.
https://www.currentresults.com/Year...nipeg/extreme-annual-winnipeg-low-temperature.
I suppose Supertech synthetic is the bees knees year-round for most of the world; here, not so much.