Fortunately, there's one easy test to figure out whether you'll have a CPU bottleneck: Monitor the CPU and GPU loads while playing a game. If the CPU load is very high (about 70 percent or more) and significantly higher than the video card's load, then the CPU is causing a bottleneck.

Is it bad if your CPU bottlenecks your GPU?

If your GPU or CPU are the bottleneck, you simply can't get more performance out of it. That's all. In fact, there is always a bottleneck in every single system, that's the simple truth. The key is to make a nice balance when making a build, i.e. not to get a too slow CPU with too powerful GPU or vice versa.

Is it better to bottleneck GPU or CPU?

Basically, the CPU sets the max framerate, based on the game. The GPU sets the max framerate, based on the game, and the resolution. And as long as your max framerate is above the refresh rate of the monitor you're using, on the games you're playing, a bottleneck really doesn't matter much.