The Memory view refresh can be very slow at times. When no program or a bare metal program that does not enable MMU is loaded, the performance is slow but somehwhat tolerable. When a freertos program is loaded, it slows down considerably. One theory is that it is related to the MMU being enabled. After disconnecting the core and performing a system reset (which will disable the MMU and clear cache) and then reconnecting, memory accesses are better (but still somewhat slow).