Poor sluggish performance after upgrading to Yosemite I am facing very sluggish performance in my MacBook Pro after I upgraded it to Yosemite. Mine is 8GB, i7 mid 2012 system.

Usually I find my unused RAM &lt;25MB even if I work in terminal, say around 8 Safari tabs open (excluded fb) and some light-weight programming editor open.  

I remember I never faced such sluggish performance in Mavericks or Mountain Lion. 
I have closed all unwanted graphical effects, but still no improvement on performance. 

Any suggestions? 



Below is the screenshot of my activity monitor:



Please note my Preview was closed while I took this shot; which is in a way super weird. 



CPU usage:
Beginning with Mavericks, Apple began using a different way of utilizing RAM called memory compression. That is why the used is so high.      

Wikipedia Virtual Memory Compression

Two things you can do are to remove the contents of the saved application state folder in your user library and remove the swap files in the /var/vm/ folder at the root of your drive. Once these have been removed, restart your computer. Let me know what you got going on after that!