All three of my rigs are doing this now as well. Different locations, different setups, all <6 months old. Probably started doing this maybe with in the last week.
Exactly same here. When I was mining in the US server all was well. This started happening about a week ago when the EU server opened. Never had these problems before when I was at the US server (now I have them here too).
Power is not an issue. I have a kill-a-watt and all is well. Also, I have the PCs (4 of them) on a 25 Amp circuit (220V) which can support up to 5500W (My rigs use around 2000 Watts).
I can confirm seeing the same here - on the eu server.
Most of the time I have seen this, the cudaminer reports "GPU #0 12345678 hashes 200kh/s"
Then the miner seems to have no work for 5-60 seconds - GPU usage is 0%
It only becomes active again after "Stratum detected new block" is received.
No connection timeout or accepted/rejected is reported in this "pause".
Aha, then so far, three of us have the same problem. Perhaps others havent noticed this yet.