I started Monkey Island up and the menu was VERY laggy. I turned the quality down to 1, and it ran just fine. When I actually got into the game, I still had some lag. I checked, and running at a quality of 3 or higher maxes out my CPU. Even with the quality at 1, I get spikes to about 85% usage.
Processor: AMD Athlon
Processor Speed: 2.4GHz
Cache Memory: 1MB on die Level 2
System Memory (RAM): 2GB
Type of Memory (RAM): DDR2
Graphics: NVIDIA GeForce 6150 SE
Video Memory: Up to 128MB (shared)
Operating System: Windows Vista Home Basic with SP1
My display is 1366x768. I was running the game at 1280x720 (or less).