Looking at the Fountain

When looking at the fountain, there is a insanely weird FPS drop. My FPS drops from 60 at Low graphics, to 2. It's very weird. It may just be my computer though. These are my computer specs.

OPERATING SYSTEM: Windows 2.6.1.7601 (Service Pack 1) CPU TYPE: Intel® Core™ i3-2100 CPU @ 3.10GHz CPU SPEED: 3.12 GHz SYSTEM MEMORY: 4.28 GB VIDEO CARD MODEL: NVIDIA GeForce 8400GS VIDEO CARD MEMORY: 2.9 GB VIDEO CARD DRIVER: nvd3dum.dll DESKTOP RESOLUTION: 1920x1080 HARD DISK SIZE: 987.01 GB HARD DISK FREE SPACE: 648.95 GB (66%) DOWNLOAD SPEED: 398.04 kB/s (3.2 mbps)