If you import an ADF on A600GS/A1200NG you have to choose an environment for that ADF to be emulated and most likely it´s not the fastest

I just started SysInfo on a custom AmigaOS 3.2.3 Setup and here is the result on an A600GS (without Turbo Option) and it´s FAST ! So it's just a misconfiguration on your side ...