Slow since upgrading to yosemite

Question

Hello I'm a new mac user and need some info.
I noticed that my mac is a bit slower since upgrading to Yosemite.
I get to see many times when opening an app the spinning colourful ball.
I did an etrecheck since i read on an over discussion that this might help resolving my problem.
Thank you
Problem description:
Slow since upgrading to Yosemite
EtreCheck version: 2.1.8 (121)
Report generated March 28, 2015 at 3:10:32 PM GMT+2
Download EtreCheck from http://etresoft.com/etrecheck
Click the [Click for support] links for help with non-Apple products.
Click the [Click for details] links for more information about that line.
Hardware Information: ℹ️
    iMac (21.5-inch, Late 2012) (Technical Specifications)
    iMac - model: iMac13,1
    1 2.7 GHz Intel Core i5 CPU: 4-core
    8 GB RAM Upgradeable
        BANK 0/DIMM0
            4 GB DDR3 1600 MHz ok
        BANK 1/DIMM0
            4 GB DDR3 1600 MHz ok
    Bluetooth: Good - Handoff/Airdrop2 supported
    Wireless:  en1: 802.11 a/b/g/n
Video Information: ℹ️
    NVIDIA GeForce GT 640M - VRAM: 512 MB
        iMac 1920 x 1080
System Software: ℹ️
    OS X 10.10.2 (14C1514) - Time since boot: 0:21:45
Disk Information: ℹ️
    APPLE HDD HTS541010A9E662 disk0 : (1 TB)
        EFI (disk0s1) <not mounted> : 210 MB
        Macintosh HD (disk0s2) / : 999.35 GB (793.45 GB free)
        Recovery HD (disk0s3) <not mounted>  [Recovery]: 650 MB
USB Information: ℹ️
    Apple Inc. FaceTime HD Camera (Built-in)
    Apple Inc. BRCM20702 Hub
        Apple Inc. Bluetooth USB Host Controller
Thunderbolt Information: ℹ️
    Apple Inc. thunderbolt_bus
Configuration files: ℹ️
    /etc/hosts - Count: 43
Gatekeeper: ℹ️
    Mac App Store and identified developers
Launch Agents: ℹ️
    [not loaded]    com.adobe.AAM.Updater-1.0.plist [Click for support]
Launch Daemons: ℹ️
    [loaded]    com.adobe.fpsaud.plist [Click for support]
    [loaded]    com.adobe.SwitchBoard.plist [Click for support]
User Launch Agents: ℹ️
    [loaded]    com.adobe.AAM.Updater-1.0.plist [Click for support]
User Login Items: ℹ️
    iTunesHelper    Application  (/Applications/iTunes.app/Contents/MacOS/iTunesHelper.app)
    uTorrent    UNKNOWN  (missing value)
    Dropbox    UNKNOWN  (missing value)
Internet Plug-ins: ℹ️
    FlashPlayer-10.6: Version: 17.0.0.134 - SDK 10.6 [Click for support]
    Flash Player: Version: 17.0.0.134 - SDK 10.6 [Click for support]
    QuickTime Plugin: Version: 7.7.3
    Default Browser: Version: 600 - SDK 10.10
3rd Party Preference Panes: ℹ️
    Flash Player  [Click for support]
    Growl  [Click for support]
Time Machine: ℹ️
    Time Machine not configured!
Top Processes by CPU: ℹ️
         1%    WindowServer
         0%    fontd
         0%    com.apple.WebKit.WebContent
         0%    AppleSpell
         0%    dpd
Top Processes by Memory: ℹ️
    283 MB    com.apple.WebKit.WebContent
    120 MB    mds_stores
    112 MB    Safari
    77 MB    Finder
    60 MB    WindowServer
Virtual Memory Information: ℹ️
    5.60 GB    Free RAM
    1.71 GB    Active RAM
    477 MB    Inactive RAM
    795 MB    Wired RAM
    1.15 GB    Page-ins
    0 B    Page-outs
Diagnostics Information: ℹ️
    Mar 28, 2015, 02:48:11 PM    Self test - passed
    Mar 26, 2015, 10:11:19 PM    /Library/Logs/DiagnosticReports/Loader_2015-03-26-221119_[redacted].cpu_resourc e.diag [Click for details]

Answer 1

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.