970 Extreme3 R2.0 high CPU package temperatures

I own an ASRock 970 Extreme3 R2.0 coupled with an AMD FX-6300 from 9 months now and while I kept monitored both CPU core and motherboard temperatures for all this time I just recently noticed a sensible increase. This increment is certainly related to the rising ambient temperature in my room, due to the seasonal change of the region I live in, while it's loosely related to the accumulation of dust, since I regularly clean the inside of my case.

I do NOT experiment with overclocking.

I observed and recorded the increment during my gaming session, which is roughly the most onerous task I demand to my system, especially with demanding and CPU-intensive games such as Battlefield 4, Planetside 2, Grand Theft Auto 5.

My FX-6300 is on the stock cooler, while my case is a Cooler Master N300, equipped with one 120mm front fan (intake), one 120mm rear fan (outtake) and a custom installed Nilox 120mm fan on the top of the case (outtake). All of which has served me fairly well thus far.

The idle temperatures of the CPU and motherboard are sligthly volatile, but they are respectively around 20-25 °C and 32-38 °C (mobo temp #1, most definitely CPU package temp), an improbable 1-3 °C (mobo temp #2), 30 °C (mobo temp #3).

Under stress the temperatures reach 52-58 °C (CPU) and 62-68 °C (mobo temp #1). I append a couple of graphs of temperatures and loads to better illustrate these stress scenarios:

Battlefield 4:

Grand Theft Auto 5:

Both reading and plotting have been done using OpenHardwareMonitor, but I cross-checked the readings with other programs such as Piriform Speccy.

While these temperatures seem to remain within the recommended bounds (60 °C for the FX-6300 and thus 70 °C (around 10 °C more) for the CPU package), are these results concerning? Should I study my case airflow in order to install additional fans? Should I consider investing into a custom cooler solution?