motherboard cooling

When I use sensor to check temperature on my ubuntu box, I noticed that the reading for i350bb-pci-6100 keeps growing. i350bb-pci-6100 Adapter: PCI adapter loc1: +68.0°C (high = +120.0°C, crit = +110.0°C) Which part on motherboard does this reading points to? What is a normal temp...

I used to be getting around 300fps+ on CSGO with these specs. i5 6500, GTX 960 4GB, Crucial Ballistx Tactical DDR4 8gb and a Gigabyte H270 Gaming 3 motherboard. I've lowered my settings to the lowest but on 1920x1080p. I didn't have this problem a month ago. I'm currently getting around 100-150...