i5 6400 at 100% usage when playing games?

[AlexSharp34]

When playing Overwatch, my i5 6400 runs at 90-100%. Task manager shows that Overwatch is using 90-99% of the usage, so nothing is open that is wasting power. It's irritating because I just bought a GTX 1070, but it's working at a low usage because of the CPU. Is this the defnition of a CPU bottleneck? Should this processor be having this much trouble? Would an i7 6700 (no k) resolve this issue?
I'll provide MSI Afterburner stats and Task Manager stats if needed.

 

[Supernova1138]

The i5 6400 is clocked rather low which hurts it, and Overwatch isn't all that GPU heavy so you could definitely hit a CPU bottleneck. The i7 6700 has faster clocked cores and hyperthreading, Overwatch seems to benefit from both. Now you should still be getting more than 60FPS with the i5 6400, so unless you have a 144Hz monitor, there really isn't much benefit in upgrading your CPU for this specific game. If you're playing something much more CPU heavy like Battlefield 1, then upgrading your CPU might offer more noticeable improvements.

 

[Vitric9]

When a game is utilizing the CPU to 100% or one CPU core or thread at 100% sometimes can lead one to a few possible conclusions
Examples may be The Game is CPU bound, or the perhaps better known: this game is a poor PC port. Or simply the engine is old
In any case it is not a horrible thing and you can monitor your statistics with RTSS(Rivatuner Statistics Server) plus MSI afterburner