all cpu's not overclocked, just standard bios settings. No highspeed gaming memory, just standard desktop pc's.
all systems run win10 (20H2)

hostid 5172 Ryzen5 2400G long-runs ~ 30.680 sec @ 5 wu's running + 1 gpu wu
hostid 5168 Ryzen5 1600 long runs ~ 28.020 sec @ 9 wu's running + 1 gpu wu
hostid 5173 Intel i7 860 long runs ~ 47.000 sec @ 5 wu's running + 1 gpu wu
hostid 6228 Athlon x4 860k long runs ~ 22.000 sec @ 2 wu's running no gpu wu

looks like MLC is specialized for these old cpu's
since my oldboy has only a small cooler i will upgrade this later in january and try running 3 wu's, currently it gets quite hot.

btw, runtime prediction is way off. Initial runtime prediction on my athlon says 1d 8h