Question Undervolting CPU questions

[snipester90]

So I recently repasted my laptops heatsink due to it overheating during gaming sessions and throttling, temperatures dropped almost 20 degrees when under max load with CPU intensive games, so I can finally use the laptop to its full potential (Temps peak at 84c degrees now, used to peak at 100). However, since I'm relatively a noob on this subject, how healthy is it for a CPU to constantly run at 80c degrees? Considering I play around 2 hours everyday, will heat affect the lifetime of the hardware?
Recently i came across the term "undervolting" to reduce Temps even more, and correct me if I'm wrong but won't limiting the power routed to the CPU also limit its clock speed? Won't undervolting mean decreased performance in games? I saw many people saying undervolting is the must do for gaming laptops, but for me it sounds counterproductive...

The CPU in question is an i7-7700hq and the laptop is an Acer Nitro 5.

 

[CountMike]

As long as it's running at temps that are less than throttling temps, it wouldn't impact CPU life span but may have some impact on paste (drying up sooner) or pads.
Undervolting may introduce some instability under high loads.

 

[Phazoner]

Undervolting doesn't affect performance. To undervolt you just pull the voltage offset in little 10mV (or 0.01V) steps and benchmark the processor to test if it can keep working without freezing or returning a BSOD (Blue Screen Of Death).

7th gen Intel Core desktop processors were too hot because they were getting much more voltage than needed, I don't know if this issue affected too laptop processors like yours. Anyway and as a example, I have a 6700k, which didn't had this issues, and I got almost a -10ºC gain undervolting to -150mV, so it is really, really worth it. And yes, having the processor over 80ºC is not good. That's the maximum recommended temperature as over 80ºC is where is believed that accelerated aging of the processors starts.

You can start configuring and testing the undervolt with Intel's XTU. It allows you to decrease the voltage offset and benchmark the processor to test if it is stable and doesn't produces instability (said freezings and BSODs). Don't worry, undervolting won't damage your PC. Once you got the minimum stable voltage offset, set it in the BIOS to make it permanent.

 

[snipester90]

So undervolting basically has no downsides but instability If not tweaked correctly, and the processor will run more efficiently. My question is why didn't the manufacturer already tune it in such a way to allow it to run cooler but at the same level of performance?