Alright guys here is the thing I'm running an Asus Gtx 760 direct CU ii and naturally i decided to Overclock it, i went by the books on this one. (turning it up 20mhz and testing) after a couple of hours of testing i hit 1200Mhz (the card is factory oc'ed to 1070mhz).
The reason i'm posting this is i'm kinda Scared should i keep going or is that enough.
note: I'm not experiencing any problems with the OC except for Tomb Raider which refuses to start.
If you are using evga precision x then use the artifact test that is built into the program to test its stability, if there is some artifacts riase the power target to 105%. As for the temperatures you are 10C under the tjmax which is 95C so you are good in that aspect, if you can sacrifice noise for power then by all means go higher.
Tomb raider is a bit odd in the way it works, so I'm not surprised it was the game that caused problems, all I can think of to help is lock the fan to 100% constantly to lower temperatures a bit and set your voltage a hair (really a tiny bit, like a couple of percent) higher. Also think about your case ventilation a little that may help temperature, thus stability both directly and in the voltage its safe to use due to temperature (there are maxes outside of temperature but you aren't near them with this level of overclock). Remember your not too hot, but I wouldn't run any hotter, allowing 10 degrees to your T max is a good idea as it allows for slight variations due to air temperature\heat-soak during long running and sensor inaccuracy, but really cooler is always better.
Having said all that that card won't explode by hitting 95 degrees C, so 85 shouldn't be causing the stability issues. Personally I think your at about the sensibly overclock to use for gaming, any more is mainly to shoot for number on benchmarks as its diminishing returns on in game performance as you turn the clocks up, plus your stressing the card harder so will have more errors\crashes and a shorter life. My advice for testing is to get fur-mark and (not or, they work different as furmark is shadercore based) 3Dmark and run a test there, its a synthetic load so it will run hotter and will show up errors before you see them in game, making it better for setting "stable" overclocks.
i turned power target up to 105% and added 2 120mm side panel fans, stressed it for about an hour and the temps maxed at 78-80 so all seems to be good .