I'm having an issue in Mavericks where my mouse periodically freezes for around 20 seconds, then comes back and everything is fine. It was also happening in the last Mountain Lion update. I have a 2008 Mac Pro with 8 GB of RAM, running Mavericks on a 120GB Vertex 2 SSD. Being an experienced PC builder and professional web developer, this lag reminds me of system latency due to memory clips. I took a screen shot of my memory activity... is it odd that 6.72 GB of RAM are "in use" with only Activity Monitor open? When I look at the individual using in the app list, none of the tasks are using an inordinate amount of RAM. What do you think is going on?