I have BEAT my 759 like a red headed stepchild, and its still going. at least 15 LN2 sessions, high volts, sloppy insulation, and its still going without a hiccup.
Used my 760 quite a bit too and it took abuse like a champ I had since sold it, and the new owner killed it, so I RMA'd for him. No problems with his new one
If your losing ram channels its most likely due to bent pins or bad cpu-pin contact.
Love evga boards and support, they just need better pi efficiency