Premiere Pro :: Choppy Slow Playback On High End Computer

A few months back, I spent a bucket of gold on upgrading to a new high end computer.

The specs:
Windows 8.1
i7-4770k 3.50GHz
32gb RAM
GeForce GTX 780
 
SSD Harddrive as main
2 extra harddrives
None of them are in RAID though.
 
But here's my problem. In the beginning, editing in After Effects CC and Premiere CC was smooth as butter.However, lately, especially Premiere has started giving me issues.
 
At the moment, I'm editing to 1080p footage, in h.264 format. There's a few effects on it, such as an overlay 720p footage, using Red Giant Looks twice (on one adjustment layer, and on the footage itself), and some other minor stuff like curves and such.
 
The effects don't seem to matter much though. Even if I play back the footage with no effects at all, playback is still choppy.
 
I have playback set to 25% size, and 1/4 resolution, and I still only get what I would guess is around 5-10 frames per second. Sometimes it drops completely, down to just 1 or 2 frames per second. Heck, at times it just doesn't update at all for a few seconds.
 
When I check my CPU usage, everything is fine. It hasn't reached max at all. RAM is still PLENTY (usually around 20gb left), and it seems that both harddrives (Premiere is running on the SSD and the files used are on another harddrive) aren't maxed out either in capacity.
 
This isn't JUST Premiere, as I said, I've seen a decline in After Effects performance as well.
 
I've attached 3 screenshots, of my CPU usages, and the 2 harddrives, showing a few minutes playback in Premiere.
 
CPU Usage:
 
SSD drive:
 
Secondary drive:
 
As you can see, apart from a few spikes here and there, none of them seem to be having issues with capping out. RAM is sitting at a steady 30% usage.