[quote]Sounded like a good idea, however I've just bought a 5v 1amp USB charger to try it and I've still got the same issue.
Does anyone know if the same issue happens with a DP monitor, connected directly to the card?
I've got three Samsung 2343bwx monitors and the Apple adapter works fine with no blinking. Did you try disabling any powersaving on the monitor or PC end? How about disabling your monitors automatic input detection? Other than that and swapping cables, I'm outta ideas. How about wiggling and reinserting your adapter/dp cable?
All power saving has been switched off (at computer and Monitor), I have also switched all monitors to manual input. I've wiggled and re-inserted the cables and adaptors so may times, I'm surprised they're not broken!
I have now connected ALL monitors with Dual link DVI cables and the USB port to the mains plug (1 amp, as suggested (thanks)). The left monitor is connected by the active Dp to DVI adaptor.
I have also made sure that the Catalyst Control Centre has been set to 'use manual detection only'.
The left monitor still switches off for a couple of seconds every so often (no pattern to it though), but then comes back on.
I guess this will have to do for now, so thanks for all your help.