Ok.. 68020+ CPU modes don't have any speed limiter and both chip ram and fast ram have exactly the same speed. You can try adjusting CPU/Chipset-slider in CPU-panel or ticking Cycle exact in Chipset-page (WARNING: in 68010+ CPU configurations ce-mode is crappy hack. It will cause compatibility problems)
Anyway, your problem is caused (at least in theory) by buggy WHDLoad slave
