An interesting thing about M7 is the use of multiplication of hashes. The multiplication is done by using GMP which allows arbitrary precision, only limited by available memory of the machine. This makes me thinking of an interesting feature to add into XMG: we can repeat many times of multiplications which literally increase the memory needed; the memory relies on the repeating times. This repeat is not just to get a pointless dataset to 'eat' memory, instead these 'huge' numbers are hashed by sha256 as the final. One of the consequence is that we can make GPU miner hard to be implemented. So it will be like tending to be a CPU coin, but I don't see any unlikely of GPU miners in the future. Another consequence is it could be memory hard (that also means not energy efficient by mining with GPU, efficiency will depend on the multiplication times), so the CPU/GPU mining could have a higher efficiency ratio compared to the pure M7, though it remains to be confirmed. It will also be possible to use varying multiplication times with time/block height etc to make GPU even harder. I am open to suggestions.
Making the coin CPU only may have it's great advantages. Look at the PrimeCoin how successful it was for a long time, the moment GPU miner was released the coin price went to ashes. People like a fair chance to mine with what they got, and many don't have a fancy GPU cards. PrimeCoin wasn't a PoS coin like Magi, if the PoW phase of the Magi is ended before the GPU miner is produced it may drive the interest and price of the coin high, no other coin has done that.
