Is there a reason why my Mac Pro all of a sudden is running slow..?

Run this and post the results here

EtreCheck

You do have the early 40 lb silver Mack Pro tower or the new black cylinder Mac Pro desktop, right?

Paste result output of Etrecheck http://www.etresoft.com

Do Safe Boot after you Boot into Recovery and run Disk Utility : Repair Disk

Backup from before yesterday?

Install OS X on another drive and Setup your system there. (Good time to upgrade to newer SSD device too).

Move off the boot drive everything but OS and Apps and user home "Library" /Users/myaccount/Library

Firstly though, you did nothing? and nothing happened?

I cannot edit my above post: saw later recommendation to use Etrecheck already mentioned.

When you see a beachball cursor or the slowness is especially bad, 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 and start typing the name.

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.

When you post the log extract, you might see an error message on the web page: "You have included content in your post that is not permitted," or "The message contains invalid characters." That's a bug in the forum software. Please post the text on Pastebin, then post a link here to the page you created.

I just tried my link and it goes to the correct site

http://www.etresoft.com/etrecheck

Just what did you do to the "complete "Restore"."?

Can you run and post the results from

http://www.etresoft.com/etrecheck