Minergate is not by any means an effecient way to mine alt-coins. If you want to mine Monero XMR, you need to download either the source; and compile a GPU Miner, and configure it to mine off one of the many pools; and do the same for a CPU Miner; that plays nice with your GPU miner.
Claymore's GPU and CPU miner are widely adopted and used, I am not sure if they work on Macs however.
You can visit the bitcointalk.org thread for Monero; and get all the information you need on the OP Thread Post including links to miners; pools, exchanges, etc.
But in closing; XMR is trading very high right now. I mined XMR two years ago and accumulated a lot of coins... this was when BTC was at 400-600 and XMR was 1/15th the current price. Across my systems; I was mining 10-20 XMR a day. But that was 2 years ago and difficulty is drastically higher now.
HERE IS A LINK TO CPU / GPU BENCHMARKS FOR MINING CRYPTONIGHT ALGORITHM COINS
HERE IS A LINK TO THE THREAD ON BITCOINTALK WHERE YOU CAN GET STARTED
In closing, you may want to look at AEON, which uses a forked version of Cryptonight, called Cryptonight-Light. It hashes at much higher rates. The coin seems to be in a bit of an unstable state development wise; issues with the new wallet release; etc, but in my experience mining the most profitable coin - at the moment - is not always the best strategy.
The key is finding the lower difficulty coins that you can mine now at a loss; that will 10x or 20x in value 12 months ahead. Finding these coins is the hard part; but that's where the money is.