I think that your problem is related to the power suply. When you play games your pc uses more watts because you stress cpu + gpu. When you pass only prime your gpu is on idle. I have the same power suply and i know that his voltaje in +12v rail is really bad. I have it with fx 8320 + 7950 and the +12v rail drops to 11.60v while playing. Your cpu draws more watts than mine so probably at full stress your +12v rail drops to 11.5v and that can cause pc restart. Also buy better cpu cooler. more than 65-70 ºC. on those cpus is dangerous and also will make your pc freeze or restart.
Have you cleaned your CPU cooler recently? The FX-9370 generates a significant amount of heat, requiring more frequent cleanings of cooling apparatuses (whether the actual cooler, or the case filters)
Any time your system shuts down due to overheating, it is wise to check the cooling to ensure that there is sufficient airflow (through the radiator fins). 95°C is extremely high for use with water cooling, and can lead to premature failure with the cooling device. Configure your BIOS settings to shut down at a lower temperature.
The Seidon 120M radiator is quite thin, and may be insufficient to cool the CPU (for perspective, the thicker Corsair H80i is also insufficient [personal experience]). Many users have found that higher-end air cooling, such as the inexpensive CoolerMaster Hyper212Evo, works more efficiently than the small 120mm AIO water-coolers. The main difference being the time it takes for the CPU to return to idle temperatures. (~1min with AIO water cooling versus ~10min with Hyper212Evo)
Consider your airflow configuration, look into any improvements that can be made to better supply cooler air to the radiator.
Your PSU is on the low-end for your setup. If it is relatively old, then you may want to look into a replacement; PSU output diminishes over time. I was able to run a similar setup for 1.5years before replacing my 750W with a 1050W.
Similarly, the ASUS M5A99FX R2 is listed as supporting the 220W processors, but only through a BIOS update. Make sure that you're using the latest BIOS version. The high TDP of the processor can lead to early failure. Many suggest using a higher quality motherboard such as a sabertooth or crosshair V, as they are designed to handle intense power requirements.
I hope this helps.
I have the same Chip and I have noticed that sometimes the screws that hold the pump to the cpu plate will loosen for some reason. I don't know if this is due to vibration or what. When this happens my temp starts to spike. I used a little semi-perm lock tight and have never had the issue again.
I run this cpu on a crosshair V formula with the factory water cooler with zero Temp issues, besides the loosen screws. I have clocked this chip @ 5.4Gigs and maintain under 60c.
I run 2 AMD R9 290 cards on a separate PSU.
MB: Asus Crosshair V Formula -Z
CPU: AMD FX-9370 w/ Water Cooler
Graphics: 2 x Sapphire Tri-X AMD R9 290
Ram: 32g x 1866
PSU: 1000w AzzA = MB
2PSU: 850w Thermotake= Video Cards
why 2 PSU ?
Problem solved with supplier. I contacted them and send an RMA, they changed the CPU but the problem was the liquid cooling. They changed it as well to another model.
Nothing related to the CPU. Thank you very much for your answers.