Maybe this is a very simple matter to you, but my stupid head is still confused as to why bitcoin mining has shifted from CPU to GPU and now to ASIC miners?
I know there is limitations on block size like an average 1megabyte for per block. So what's the issues there so that force to upgrade the miners?
The block size hasn't increased here, so miners need more powerful hardware.
Then what the cause for shifting?
With the help of CPU on GPU you can mine any coins, but ASIC on a certain algorithm can work like thousands of CPUs and GPUs, because this ASIC is designed for a specific algorithm.