Im worried about Overclocking my GTX 970

[ISetsunaI]

Alright, i have been overclocking for a good few weeks now. I can keep my GPU underload at 1560MHz + 120MHz for Mem Clock. The temperature as ive been told is really really good. Idle it is at 25C without the fans spinning and when it is underload the temp varies from 45C-55C. Of course, my computer ends up sounding like an industrialized leaf blower, but hey, i don't really care since i use a headset.

So heres a few questions

1)Im worried about the average lifespan of a graphics card, is my graphics card going to die if i keep overclocking games like FarCry4? (My gaming sessions can vary from 2 hours to 7 hours, but i always turn OC off when i exit out of a game and give it a few breaks)

2)Okay maybe i lied a little. The leafblower gets annoying after a while. I always get really really worried after it hits 55C. Ive been told it's okay to hit that. Is it okay to go at a stable temp around 60-65?

3) TDP. It says the TDP of a GTX 970 is 145. Does that include the fans spinning etc? And if it's overclocked how much higher is it? My average TDP for the system is 350 with my rig. With a powersupply of 750 wats can i do a 2 way SLI and overclock?

4)I still don't get how GPUs die. Do they degrade or do they just croak? If i keep getting high temps (hasnt happened yet, but just in case) it's just the thermal paste right? So if i overclock around 1560MHz, does that mean my GPU decays faster? Please explain!

 

[Suztera]

Overclocking can reduce the lifespan but you would probably upgraded before it dies if maintained well.
Actual TDP is 160-180W. Overclocking will push that higher. As long your gpu does not go over 80C constantly it is fine. They can handle higher temps but there is safety measures to shut it down before it melts the gpu.

A decent 750W is enough for a SLI GTX 970 with overclocking headroom.
High temps can be the thermal paste drying but the GPU is not broken yet. You probably won't see it die as you would have upgraded it.

 

[ISetsunaI]

So if i keep it at 45-50C even at 1560MHz it would still have an average life span of what, 3 years? Also, when (about when) should i change my Thermal Paste? Every 6 months?

 

[Suztera]

You know when to change thermal paste, when the temperature becomes hotter than normal and is not because of the climate /room temperature.
You can probably make it last longer than 3 years but by that time, there will be newer gpu with newer tech, you probably would have upgraded if you playing games and want to keep up the graphics.