1% stale is no issue. You are better in this case to have fewer rejected shares. In the case of the 134/1/81...that 81 is almost 40% of your shares...so 2mhs doesnt help if you are losing 4 out of 10 shares. I would need to know gpu and oc settings to advise what to lower. But definetly too high one or both... core/memory.
hi i use gtx 1060 6gb sc with 2 overclock configs
low config use +0 core clock which it does not crash my computer, + 1000 memory clock
high config use +100 core clock +1000 memory clock
My gtx 1060 is superclocked so i can't increase core clock much without it crash my pc WHEN i work on it
when i work on my computer i use the low config to prevent my pc from crashing it goes for 25.9 mh/s
when i go to sleep i leave my pc on screen saver and i use high config and it did not crash my pc when it's on screen saver. it goes for 26.550 mh/s
so the data i mention 134/1/81 is when it was on the high config
I did'nt test when using low config to check if i have less rejected shares, i'll test this night and see.