I own 15 pcs of 5*R9 390x and 5*480x rigs.Installed V7.3 version and mining ether solo.
3 days ago I asked for a static IP from my telecom operator.
Yestereday, my rigs quited mining.I changed my pool (from coinotron to coinmine.pl).My static ip rigs gave up mining however my internet connection is fast and seems stable.
Do you experience such a problem?I connect from Serbia to Europe servers.The room is a well cooled room, with low humidity, electricity understructure is a 3 phase and grounded.So the temperature and power are eliminated among the possible causes.
with that big of a hash, why don't you mine at ethpool?
ethpool has also EU node.
CDM v7.3 is the most stable miner of all and should not have any issues mining at major ETH pools.