Hoptoit McNegropants

Just yesterday, I had been playing the Dota 2 beta on reasonably high settings with the game taxing somewhere between 1 and 2 gigs of the 4 gigabytes of RAM. Today, the game now has significant framerate drop. I lowered the graphical settings to the absolute minimum and yet the framerate still remained around 10 fps. Also, other performance such as loading up web pages now takes much longer. The CPU usage is bouncing between one and five percent, yet the physical memory currently being used is around 1.5 gigabytes. I usually check my performance consistently and the CPU MAY be lower however the RAM usage is significantly higher and I cannot identify any programs that I didn't notice last time.