https://www.bicyclerollingresistance...prix-5000-s-tr
Interesting. BRR measured the same-ish rolling resistance for a given pressure, but the tire has also gotten ~1.5mm smaller, which means you'd have to run it at a slightly higher pressure. So the tire is probably slightly faster. Maybe like 1 watt.
Jarno also mentions that the casing is stiffer.
afaik the old gp5k wasn't exactly known to be supple (relative to other race tires) so this might not be great news.