Slow iMac since upgrading to Yosemite

Question

My iMac seems to be showing me lots of color wheels and is slow to start and shutdown.  Here is the etrecheck log and advice would be greatly appreciated. 
Thank you,
John
EtreCheck version: 2.1.6 (109)
Report generated January 25, 2015 at 8:28:23 AM EST
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Click the [Details] links for more information about that line.
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Hardware Information: ℹ️
  iMac (21.5-inch, Mid 2011) (Technical Specifications)
  iMac - model: iMac12,1
  1 2.5 GHz Intel Core i5 CPU: 4-core
  8 GB RAM Upgradeable
  BANK 0/DIMM0
  4 GB DDR3 1333 MHz ok
  BANK 1/DIMM0
  4 GB DDR3 1333 MHz ok
  BANK 0/DIMM1
  empty empty empty empty
  BANK 1/DIMM1
  empty empty empty empty
  Bluetooth: Old - Handoff/Airdrop2 not supported
  Wireless:  en1: 802.11 a/b/g/n
Video Information: ℹ️
  AMD Radeon HD 6750M - VRAM: 512 MB
  iMac 1920 x 1080
System Software: ℹ️
  OS X 10.10.1 (14B25) - Time since boot: 0:30:9
Disk Information: ℹ️
  ST3500418AS disk0 : (500.11 GB)
  EFI (disk0s1) <not mounted> : 210 MB
  Macintosh HD (disk0s2) / : 499.25 GB (155.30 GB free)
  Recovery HD (disk0s3) <not mounted>  [Recovery]: 650 MB
  OPTIARC DVD RW AD-5690H 
USB Information: ℹ️
  Apple Inc. FaceTime HD Camera (Built-in)
  Apple Inc. BRCM2046 Hub
  Apple Inc. Bluetooth USB Host Controller
  Apple Computer, Inc. IR Receiver
  Apple Internal Memory Card Reader
Thunderbolt Information: ℹ️
  Apple Inc. thunderbolt_bus
Gatekeeper: ℹ️
  Mac App Store and identified developers
Kernel Extensions: ℹ️
  /Library/Application Support/VirtualBox
  [loaded] org.virtualbox.kext.VBoxDrv (4.3.12) [Support]
  [loaded] org.virtualbox.kext.VBoxNetAdp (4.3.12) [Support]
  [loaded] org.virtualbox.kext.VBoxNetFlt (4.3.12) [Support]
  [loaded] org.virtualbox.kext.VBoxUSB (4.3.12) [Support]
  /System/Library/Extensions
  [loaded] com.rim.driver.BlackBerryUSBDriverInt (0.0.74) [Support]
  [not loaded] com.rim.driver.BlackBerryUSBDriverVSP (0.0.74) [Support]
Launch Agents: ℹ️
  [loaded] com.citrixonline.GoToMyPC.LaunchAgent.plist [Support]
  [loaded] com.citrixonline.GoToMyPC.LaunchAgent.plist.final [Support]
  [invalid?] com.oracle.java.Java-Updater.plist [Support]
  [running] com.rim.BBAlbumArtCacher.plist [Support]
  [running] com.rim.BBLaunchAgent.plist [Support]
Launch Daemons: ℹ️
  [loaded] com.adobe.fpsaud.plist [Support]
  [running] com.citrixonline.GoToMyPC.CommAgent.plist [Support]
  [loaded] com.microsoft.office.licensing.helper.plist [Support]
  [invalid?] com.oracle.java.Helper-Tool.plist [Support]
  [running] com.rim.BBDaemon.plist [Support]
  [not loaded] org.virtualbox.startup.plist [Support]
User Launch Agents: ℹ️
  [loaded] com.google.keystone.agent.plist [Support]
  [not loaded] org.virtualbox.vboxwebsrv.plist [Support]
User Login Items: ℹ️
  iTunesHelper Application Hidden (/Applications/iTunes.app/Contents/MacOS/iTunesHelper.app)
  Dropbox Application  (/Applications/Dropbox.app)
  Android File Transfer Agent Application  (/Users/[redacted]/Library/Application Support/Google/Android File Transfer/Android File Transfer Agent.app)
Internet Plug-ins: ℹ️
  Flip4Mac WMV Plugin: Version: 2.4.4.2 [Support]
  FlashPlayer-10.6: Version: 16.0.0.287 - SDK 10.6 [Support]
  QuickTime Plugin: Version: 7.7.3
  Flash Player: Version: 16.0.0.287 - SDK 10.6 [Support]
  Default Browser: Version: 600 - SDK 10.10
  SharePointBrowserPlugin: Version: 14.2.0 - SDK 10.6 [Support]
  Silverlight: Version: 5.1.20125.0 - SDK 10.6 [Support]
  JavaAppletPlugin: Version: 15.0.0 - SDK 10.10 Check version
User internet Plug-ins: ℹ️
  CitrixOnlineWebDeploymentPlugin: Version: 1.0.105 [Support]
Safari Extensions: ℹ️
  1Password [Installed]
  Evernote Web Clipper [Installed]
  YoutubeWide [Installed]
3rd Party Preference Panes: ℹ️
  Flash Player  [Support]
  Flip4Mac WMV  [Support]
  GoToMyPC Preferences  [Support]
Time Machine: ℹ️
  Auto backup: YES
  Volumes being backed up:
  Macintosh HD: Disk size: 499.25 GB Disk used: 343.95 GB
  Destinations:
  Data [Network]
  Total size: 2.00 TB
  Total number of backups: 124
  Oldest backup: 2012-11-05 01:37:01 +0000
  Last backup: 2015-01-25 12:21:30 +0000
  Size of backup disk: Excellent
  Backup size 2.00 TB > (Disk size 499.25 GB X 3)
Top Processes by CPU: ℹ️
      5% WindowServer
      0% BBLaunchAgent
      0% fontd
      0% AppleSpell
      0% notifyd
Top Processes by Memory: ℹ️
  137 MB Finder
  112 MB mds_stores
  77 MB Dropbox
  60 MB WindowServer
  60 MB Dock
Virtual Memory Information: ℹ️
  5.65 GB Free RAM
  1.44 GB Active RAM
  393 MB Inactive RAM
  1.11 GB Wired RAM
  1.10 GB Page-ins
  0 B Page-outs
Diagnostics Information: ℹ️
  Jan 25, 2015, 07:58:48 AM Self test - passed

Answer 1

Please read this whole message before doing anything.
This procedure is a test, not a solution. Don’t be disappointed when you find that nothing has changed after you complete it.
Step 1
The purpose of this step is to determine whether the problem is localized to your user account.
Enable guest logins* and log in as Guest. Don't use the Safari-only “Guest User” login created by “Find My Mac.”
While logged in as Guest, you won’t have access to any of your documents or settings. Applications will behave as if you were running them for the first time. Don’t be alarmed by this behavior; it’s normal. If you need any passwords or other personal data in order to complete the test, memorize, print, or write them down before you begin.
Test while logged in as Guest. Same problem?
After testing, log out of the guest account and, in your own account, disable it if you wish. Any files you created in the guest account will be deleted automatically when you log out of it.
*Note: If you’ve activated “Find My Mac” or FileVault, then you can’t enable the Guest account. The “Guest User” login created by “Find My Mac” is not the same. Create a new account in which to test, and delete it, including its home folder, after testing.
Step 2
The purpose of this step is to determine whether the problem is caused by third-party system modifications that load automatically at startup or login, by a peripheral device, by a font conflict, or by corruption of the file system or of certain system caches.
Please take this step regardless of the results of Step 1.
Disconnect all wired peripherals except those needed for the test, and remove all aftermarket expansion cards, if applicable. Start up in safe mode and log in to the account with the problem. You must hold down the shift key twice: once when you turn on the computer, and again when you log in.
Note: If FileVault is enabled in OS X 10.9 or earlier, or if a firmware password is set, or if the startup volume is a software RAID, you can’t do this. Ask for further instructions.
Safe mode is much slower to start up and run than normal, with limited graphics performance, and some things won’t work at all, including sound output and Wi-Fi on certain models. The next normal startup may also be somewhat slow.
The login screen appears even if you usually log in automatically. You must know your login password in order to log in. If you’ve forgotten the password, you will need to reset it before you begin.
Test while in safe mode. It will be slow, but there should be no beachballing. Same problem?
After testing, restart as usual (not in safe mode) and verify that you still have the problem. Post the results of Steps 1 and 2.