Yes. Better than a v1 Race King in the wet / loose and feels faster in the dry or on hardpack. Really good tyres, used them for the TDR after trying a few options and the rear was thin but workable still at the end. Loses a bit of volume to the 2.2 R.K. but not enough to worry about. Std version works TLR easily.
Ikons and SB8s, that file tread isn’t as quick-rolling as it looks compared to something like a Nano or Saguaro with a central raised strip and they’re at a disadvantage on softer ground.
But if I wanted pure speed on dry hardpack, new-pattern Race Kings, no doubt.
edit to add,
that rolling resstance test website – looks like a steel drum test. A good constant to use for all tyres but not as representative of riding off-road as on smooth tarmac. I expect the poor figures for the Ikon + SB8 on that test wouldn’t be so bad on something like a dirt road roll-down test, or maybe they just use a tougher casing (Jan Heine’s blog says that casing is a huge part of RR but off-road that’s a compromise point).