It’s a 1mhz processor and for scrolling to be smooth you need to move 2k of memory within one frame. That means if you get the timing right you have at most 1 m

It’s a 1mhz processor and for scrolling to be smooth you need to move 2k of memory within one frame. That means if you get the timing right you have at most 1 million/60 clock ticks, which is about 16666, to do the scrolling and everything else you need to do. You really can’t do that ‘with ease’ which is why c64 games typically divide up the screen so the scrolling area is smaller.