Slow performance, weird memory usage, hanging when closing safari tab

Question

Hi, i recently noticed that my MacBoo Pro was with low performance after some hours of use.
I'm a heavy user, so I try to monitor what might be causing it. What i note was:
After restart (or fresh start), my computer was ok;
I use applications like adobe Lightroom and VMWare Fusion;
Then I star feeling like Safari was too slow to open pages - I thought it was the internet link first, but even local webpages are slow. I notice that when a click to close a tab, it take almost 2 sec to do it. The same when click to open any link on that page.
I start the activity monitor, but my proc usage are low. Then, I notice the (weird) memory usage:
Take a look at "memory used". I closed all applications before take this screenshot. i've trying to identify what is consuming this memory, but.. no success.
Anyone has any idea what can might be causing it?
My HW information:
all my apps are updated.

Answer 1

Memory usage was normal when you took that screenshot.
When you have the problem, note the exact time: hour, minute, second.  
These instructions must be carried out as an administrator. If you have only one user account, you are the administrator.
Launch the Console application in any of the following ways:
☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
☞ Open LaunchPad. Click Utilities, then Console in the icon grid.
The title of the Console window should be All Messages. If it isn't, select
          SYSTEM LOG QUERIES ▹ All Messages
from the log list on the left. If you don't see that list, select
          View ▹ Show Log List
from the menu bar at the top of the screen.
Each message in the log begins with the date and time when it was entered. Scroll back to the time you noted above.
Select the messages entered from then until the end of the episode, or until they start to repeat, whichever comes first.
Copy the messages to the Clipboard by pressing the key combination command-C. Paste into a reply to this message by pressing command-V.
The log contains a vast amount of information, almost all of it useless for solving any particular problem. When posting a log extract, be selective. A few dozen lines are almost always more than enough.
Please don't indiscriminately dump thousands of lines from the log into this discussion.
Please don't post screenshots of log messages—post the text.
Some private information, such as your name, may appear in the log. Anonymize before posting.