Thanks for your replies.
I am using ccminer 2.2.1.
I was not ware of this pb described with Algo Pool

was mining like 5 years ago and just came back to it now ... things have changed a lot since then

i am busy making some research before really investing in it (i mean build a GPU miner).
The following question might seem stupid but, i am a bit surprised by the different Hash speed i have using different Algo on the same cards (Nvidia 1070). While i get like 3200MHz on Blade2s, it drops to 12Mhz using Equihash for example.
Therefore, i am a bit confused to find the correct Algo/Coin with best return ... but will get there lol