Thanks for the ideas , guys .

Some clarifications . My system is is 2 x 7200 + 7200 Hc + 2 x 5000 + 1 x D2500 . When its bad , it sounds worse than my loo at 4am ! Most of the time this not the case ; this is infuriating.

Ronnie , it would be interesting to drop the RJ45 and AC11 . I wont get a chance for a while but it would make sense to rule out the ' new tech ' first .

~M~

Mostly harmless. Comfortably numb.