I have high cpu usage on fortnite and bf4. I have I5 8400 (3.8ghz) gtx 1080 and 8gb (3200mhz) ram (later upgrade to 16gb). In fortnite My cpu usage is around 85% and gpu 60% fps is usually around 120-170 on epic settings and In bf4 both are In 100% on ultra and fps is around 100-130 on 64 multiolayer match. I don't believe it is bottleneck. But what i have to do with fortnite to get gpu usage higher and In bf4 cpu usage lower. It is not heating problem. I play 1080p 144hz monitor. Sorry for bad english hopefully you understand