You have to understand just how bad the design of the 6200 is to understand the problems you are experiencing. They pretty much took a Quadra motherboard and dropped a PowerPC chip on it, the problem is that the PPC does things differently than an 040, so it is not a drop in swap. Another problem with the 6200 is that the CPU has to act as a middle man between components on the motherboard. Nothing is able to communicate independently with anything else without the CPU getting involved. This takes up so many clock cycles that the 603 chip actually ran slower than the 601 in many instances, which really isn't fair to the 603 since it is a actually superior to the 601. The CPU was also saddled with regulating the timings required by the various components which all operated at different rates rather than using components that all run at the same speed. A separate multiplexing chip would have helped a lot, but they were trying to avoid the expense of adding one. Back during those days Apple made several models that seemed like they were thrown together just to clear their old parts inventory so they wouldn't have to design completely new models from scratch.