Troubleshooting software?

Hi, just wanted to know if there was any software for Mac that would allow me to log what my system does ad what processes it uses?

Reason I ask is because at random times whether I am playing the sims or writing in scrivener or using Firefox or finder my system will suddenly slow down and things get jerky and the mouse becomes difficult to navigate on screen. I check the activity monitor and my ram is not being used more than normal. I wan to troubleshoot to hopefully resolve that issue.


Thanks in advance.