Random FPS drops with no obvious cause

Today I started up League, jumped into a match and found out the game was UNPLAYABLE.

Here are the stats I normally see in game:

FPS: 250+ Ping: 80-95

Every few seconds, especially when my camera is not locked to my champion. The FPS will dip down first to 75, then to lower then 30 making everything glitch out and laggy. There is no reason for this, on the lowest settings my game goes above 350fps with no problems. On the highest (What I always run on) It's 250 solid. Big team fights might be able to drag it down to around 175 but that's the lowest I've ever seen it go.

First to disclaim a few things so I don't get useless replies:

1. No, it's not a ping issue.

2. No, it's not a hardware issue

3. No, I'm not running some other program like Lolreplay that could cause glitches like it did in the last patch (Bringing peoples FPS down to like 1

4. No I've never had this issue before

5. Once again, NOT a hardware issue or ping issue

This is clearly a case of bad coding, or something going wrong in the games files cause this is not my computer doing this.