is my processor causing frame stuttering in game?

[Comoletti]

When I am playing games, I get these very annoying and frustrating frame stuttering. Even a few times, the screen was stuck on one frame for a whole second. I feel like my processor is the reason for this as it is the lowest grade piece of hardware in my pc. I feel like it is bottlenecking it or something?
Here is what I have:
GPU: MSI GTX 660 OC edition
CPU: Intel core i3-2120
RAM: 6GB(2GB + 4GB)
I play BF4 in high settings and I get 30-55 fps which is playable.

 

[MADVIU]

Yeah, it looks like your i3 is bottlenecking your 660. What is your PSU?

 

[Rationale]

It may be the i3, seeing as it's a weaker and older version. However, you'll also want to make sure you don't have the resolution scaling set past 100%, and that you're not using a ton of antialiasing. Always a risk of running out of VRAM, since AA really artificially increases the resolution past 1080p and scales it back down. Last time I got stutter like that, it was on a 768MB card in Battlefield 3 whenever I turned the textures up to ultra.

Fortunately the LGA 1155 socket has some very strong CPUs on it still, so if it really does end up being the i3 it'll be easy to replace. Still, I'd look at resolution scaling and antialiasing as the first possibilities, partially because those are so easy to check, as opposed to testing for a CPU bottleneck.