Dramatic FPS drop with ENB, only when looking in certain direction

[kefka95]

I recently started using True Vision ENB (what a difference compared to vanilla, like playing an entirely new game!). I did experience an FPS drop after activating the ENB, but my game still runs at a reasonable 30 FPS most of the time. However, I'm having an issue in certain locations where the FPS will suddenly drop to almost nothing (down to 1 or 2 FPS), but only if I'm looking in a specific direction. For example, in Riften, as soon as I look in the direction of Mistveil Keep, the FPS plummets. If I look in a different direction, or do anything else in town that doesn't point me toward Mistveil Keep, the game runs perfectly fine - the FPS drop only occurs if my character is looking at that specific area. I've seen this same issue in several other areas as well (most commonly in towns or villages).

 

Here's the strange part. If I alt-tab out of the game and get back into it, it resumes running at its normal speed, including in the areas that previously ran at 1-2 FPS. However, as soon as I look at the map and then go back to the game, or enter a building and come back out, it goes right back to the 1-2 FPS, and I have to alt-tab out of the game to get it working decently again. Any ideas as to what would cause this? My specs are below:

 

CPU: i5-3570K

GPU: Radeon HD 7870, 2 GB (drivers are current)

RAM: 8 GB, DDR3 1600