Both --extreme and --optimize disabled intel_pstate turbo on the theory
that frequency changes cause jitter. On HWP-capable CPUs (i7-10875H) the
performance governor already holds clocks steady at the top; disabling
turbo only caps all cores at the 2.3GHz base (~64% of clock headroom
thrown away), starving SuperDirt's DSP and causing the very xruns/crackle
it was meant to prevent. Now pins min/max_perf_pct=100 with turbo on.