I7 4790K Temps Hitting 77C

[JRiva]

Good Morning Folks (Or Evening, depending on when you read this post),

I recently put the following build together:

Motherboard: Asus Z97-A ATX

Processor: Intel Core i7-4790K 4.1 GHz

Cooler: Stock Cooler

Memory: Corsair Vengeance 16GB (2x8GB) DDR3 1600MHz

Hard Drives: Samsung 850 EVO 250GB SSDD & Seagate 500GB SATA 6Gb/s 3.5" 7200rpm

Optical: LG DVD+-RW

GPU: Asus STRIX GTX970 4GB GDDR5

Case: Corsair Carbide 200R

PSU: Corsair CX750M 750 Watt

Windows Version: 8.1 Professional

Min CPU Temp: 39-40C

Max: 77C under load (momentary, and goes back down to around 70C-72C quickly)

The Temperature in the room where the PC is located is 20C.

The PC is partially enclosed (not an option to change its location, otherwise I would as I know this can help with overall temps as well)

I am using CPUID HWMonitor to monitor my temperatures. I am receiving around 40C during non-stressful operations on my Package/Cores. During PC gaming sessions I am hitting the low to mid 70's, the highest reading I got was 77C. The processor seems to sit at around 70C while under load, and creeps upwards to mid 70's as gameplay continues, then tends to settle back down to low 70's.

My knowledge about temperatures in regards to hardware is limited, and I am aware of the 74.04 TCase IHS spec for the 4790K. Is this the temperature that my cores should not go past? At what point does my CPU start to take damage from heat? Are there tweaks that I can make with an adept, but not expert understanding of BIOS/Software suites? Does an aftermarket cooler void my warranty on my CPU?

Thanks in advance for your advice.