GPU mining is good for altcoins. Both Nvidia are amd are good gpu's for mining but there is a problem and the problem is both amd and Nvidia doesn't work at the same time on 1 coin. Means if Nvidia works on a coin then amd doesn't work on it. Only one gpu work at one time. But there is also a cryptonight project where both work at the same time. Till now I have found only 1 cryptonight(Ryo coin) algo where both of them work and work very well. If someone here knows any other coin where these both gpu's work at the same time. please let me know I would like to try it.