the cpu might be getting too hot and the auto safety on the chip is cutting it off. see if the fan is clogged with dust stopping it working properly. only other thing I can think of is a faulty psu, this can cause all sorts of problems.
Huawei P10 review
1995-2015: How technology has changed the world in 20 years
An overview: What leading creative agencies are doing to improve diversity
New iPad, iPhone SE & Red iPhone 7 on sale now
Synology invites you to visit them at Insomnia on 26th – 29th August. Book your tickets now and visit Synology.