I use mine at 4.3Ghz with a very mild voltage increase. Works like a champ, but sometimes it shows its age.
In gaming so far it's great and paired with a GTX 1070 has given me some drops from 60fps only in Watchdogs 1 & 2, Witcher 3, Deus EX, Grand Theft Auto 4 & 5 and in large battles in Ashes of the Singularity. Nothing too serious, but a better cpu would be preferable for sure.
It's the apps that give me some trouble, compressions and decompressions, it is a slouch in encrypted files, which thankfully I only use for the house documents and oh I wish it was faster in video encodings for my amateurish hobbyist Youtube channel.
Speaking of which, I have uploaded a huge bunch of Overclocked gaming benchmarks with frametimes and whatnot
here.
Last year I published the benchmarks with the 970 vs a i7-860 and a Q9550, which you can find in my signature. This year I plan to do the same with 1070 but vs i7-860 and i7-8700k. Spoiler alert, the 2500k wins in the vast majority of the tests with the 1070 vs the i7-860 as well, with the honorable mention that the i7-860 ain't doing too bad either. . You can't beat that clock with hyperthreading.
For me as a home user, the Sandy Bridge was the best cpu from Intel during the past few years. Cannon Lake will be the next big thing.