660 ti crashes on demanding games!

[indranil.mitra26]

Specs:-
Asus GTX 660 ti DC2T
Intel core i7 3770 (non k)
Asus Maximus V Gene
16GB Corsair Vengeance (4x4)
Corsair GS 600 PSU
Stock Intel CPU Cooler.

My rig is almost 4 years old and lately i've been suffering from crashes, mostly freezes (sound continues) on almost all demanding games. I had found a workaround, i.e to underclock my gpu by 10 MHz which fixed the problem.
And yes, I had tried reinstalling drivers by ddu multiple times. I forgot the last stable driver but I tried rolling back to an old driver and it crashed on me still (with significant lower performance, since old driver). I have been using the latest driver ever since the 10 Mhz underclock but recently since the last few weeks even that isn't helping anymore. Games like Witcher 3, Hitman 2016, Mafia 3 still crash on me. I am almost sure that my PSU is just fine. My max CPU temps reach around 85 C while playing demanding games. As to whether it's caused by failure of RAM, i'm not sure. I tried playing on one random 4gb stick and Mafia 3 worked but Witcher 3 crashes instantly.
I have reseated my gpu, made sure everything inside my chassis is clean. Any help is appreciated.

 

[indranil.mitra26]

EDIT: I underclocked it to -26 Mhz and it seems to have fixed the problem. But I'm still not sure as to what is the root cause of the problem and what this signifies?

 

[smorizio]

sounds like the thermal paste un the gpu is drying out and causing the card to run hot. if it not a temp issue it might be a part on the gpu is starting to fail.

 

[indranil.mitra26]

sounds like the thermal paste un the gpu is drying out and causing the card to run hot. if it not a temp issue it might be a part on the gpu is starting to fail.

My GPU temps are hovering around the 70 C mark during gameplay. I dont think its a temperature issue. :/