That would be great! You'll need to revert to A23 for the measurement to be correct though, with the patch applied. If you need help let me know.
I'm not sure. The logs will tell us which performance counter is used (either HPET or something else). I don't think profiling the game will help us much. Maybe monitoring temps during slowdowns?
I looked this morning but I couldn't find a link to an email or something. I'd rather not have to go through L1 support, especially since I do not have access to such a processor. But if we can get in touch I'd definitely try it.
My guess is similar. 0 A.D. starts hogging the CPU until it overheats, throttles, setting game time counters off, (massive slowdown) then after cooling a bit, it goes back to full speed, causing speedups.