I have a weird thing, when mining PIRL I have 29mh/s but when I try to mine ETH Im getting 18mh/s. I tried ethermine and nanopool but nothing changed. Anyone got an idea ? I should get the same speed since its the same algorithm right ?
No, your hash rate will depend on the difficulty for a particular coin, Eth difficulty is way up there with BTC and LTC. Look at the difficulty level of Pirl compared to Eth.