thanks all for your replies, definitely a great community !
what i understood, if my T9 is not running 24x7, i would have very few chance to be successful using the PPLNS : (
have 3 days running but unfortunately interment, so, it looks like that is no good!
thanks
You need them to run 24/7 to get the "best bang" for your buck. Otherwise, it's costing you more money by just sitting there not getting anything in a return.