The fix actually involves that the ship doesn't move at the speed it says, rather it moves at 5% speed (dunno what the exact values are) and the REST of the universe moves the remaining 95% speed relative to the ship (essentially, your ship moves, but the universe moves too and faster than the ship moves, together it looks perfectly in-sync.. but behind the scenes ,p) Well I mentioned the fix was crazy.
That way, the precision issue doesn't happen as much (planets only have 1 huge part essentially, so no issue there when they move faster or have some precision problem)
But yeah, since speed acceleration goes to 100000x that also means 3850m/s * 100000 ...... if you have 200 parts, even a single very last digit mismatch between 5 and 6 can rip your ship apart into 200 single parts (more often than not, it actually explodes rather pretty ;p) since for just 1 single step of the calculations, the forces exceed the specified limits of parts.
But to be fair, PhysX is an incredible Physics engine. You can have rovers, robot arms with magnetic grip, or your entire space ship can have giant wheels for vertical landing and driving around on planets. Try that in orbiter, hah
I mean, try that in any physics engine where you can start from a planet land on a moon 12 hours later, drive around, then get out, and walk around with realistic ragdoll physics while you topple down a hill ;P