Thats awfully defensive old chap, just so we are clear i give zero cares what you do or why you do it and i extend that to everyone. If you like using closed source operating systems then good for you. I however do not as you correctly determine and for the record I do not worship linux rather I avoid centralised control and exploitation wherever I am able to and this includes propitiatory software and I urge everyone to inspect carefully to what and whome they bind themselves for there are many offers made to the blind in order to exploit and harness there energy. And after all that is said the ones paying attention notice that Phoenix Miner is closed source so yeah, not ideal....  All the best with those 6600's in time they will yield good results but for me the density of hash is to small, i prefer bigger cards and smaller rigs in case you had doubts about it