Microprogramed controlled control unit is very much similar to CPU. In CPU the PC is used to fetch instruction from the main memory, but in case of control unit, microprogram counter is used to fetch the instruction from control store.

But there are some differences between these two. In case of fetching instruction from main memory, we are using two signals MFC and WMFC. These two signals are required to synchronize the speed between CPU and main memory. In general, main memory is a slower device than the CPU.

In microprogrammed control the need for such signal is less obvious. The size of control store is less than the size of main memory. It is possible to replace the control store by a faster memory, where the speed of the CPU and control store is almost same.

Since control store are usually relatively small, so that it is feasible to speed up their speed through costly circuits.

If we can implement the main memory by a faster device then it is also possible to eliminate the signals MFC & WMFC. But, in general, the size of main memory is very big and it is not economically feasible to replace the whole main memory by a faster memory to eliminate MFC & WMFC.