That's really strange, JIT WinUAE is MANY times faster than non-JIT on my system.
About your screen caps - I can't work out the readings given in sysinfo.
The first one (817R3) shows a locked 7.09Mhz speed, as if you've selected "run A500 speed" in the CPU section and not "fastest possibe".
Selecting the former will limit the possible performance gain from running JIT.
Did you use the configeration "test" I'd provided with WinUAE8.17R3?