Why is my MacMini 6.1 always so high in Memory Used?

Question

Hi,
I was wondering if anyone could help me figure out why my MacMini keeps running slowly... I think it's to do with Memory Used, but I'm only guessing.
Thanks.
EtreCheck version: 2.0.11 (98)
Report generated 6 November 2014 10:39:57 pm AEDT
Hardware Information: ℹ️
    Mac mini (Late 2012) (Verified)
    Mac mini - model: Macmini6,1
    1 2.5 GHz Intel Core i5 CPU: 2-core
    16 GB RAM Upgradeable
        BANK 0/DIMM0
            8 GB DDR3 1600 MHz ok
        BANK 1/DIMM0
            8 GB DDR3 1600 MHz ok
    Bluetooth: Good - Handoff/Airdrop2 supported
    Wireless:  en1: 802.11 a/b/g/n
Video Information: ℹ️
    Intel HD Graphics 4000 -
        TOSHIBA-TV 1920 x 1080 @ 50 Hz
System Software: ℹ️
    OS X 10.10 (14A389) - Uptime: 11 days 5:12:28
Disk Information: ℹ️
    APPLE HDD HTS545050A7E362 disk0 : (500.11 GB)
    S.M.A.R.T. Status: Verified
        EFI (disk0s1) <not mounted> : 210 MB
        Macintosh HD (disk0s2) /  [Startup]: 499.25 GB (156.01 GB free)
        Recovery HD (disk0s3) <not mounted>  [Recovery]: 650 MB
USB Information: ℹ️
    Apple Inc. BRCM20702 Hub
        Apple Inc. Bluetooth USB Host Controller
    Apple, Inc. IR Receiver
    Microsoft Microsoft 5-Button Mouse with IntelliEye(TM)
Thunderbolt Information: ℹ️
    Apple Inc. thunderbolt_bus
        Promise Technology, Inc. Pegasus R-Series
Configuration files: ℹ️
    /etc/hosts - Count: 45
Gatekeeper: ℹ️
    Mac App Store and identified developers
Kernel Extensions: ℹ️
        /Library/Extensions
    [loaded]    com.promise.driver.stex (5.2.10 - SDK 10.9) Support
        /System/Library/Extensions
    [not loaded]    at.obdev.nke.LittleSnitch (3876 - SDK 10.8) Support
Launch Agents: ℹ️
    [not loaded]    com.adobe.AAM.Updater-1.0.plist Support
Launch Daemons: ℹ️
    [failed]    com.adobe.fpsaud.plist Support
    [invalid?]    com.adobe.SwitchBoard.plist Support
    [loaded]    com.promise.bgasched.plist Support
    [running]    com.promise.BGPMain_R.plist Support
    [loaded]    com.promise.emaild.plist Support
User Launch Agents: ℹ️
    [loaded]    com.adobe.AAM.Updater-1.0.plist Support
    [loaded]    com.adobe.ARM.[...].plist Support
User Login Items: ℹ️
    iTunesHelper    ApplicationHidden (/Applications/iTunes.app/Contents/MacOS/iTunesHelper.app)
    uTorrent    ApplicationHidden (/Applications/uTorrent.app)
    Dropbox    Application (/Applications/Dropbox.app)
    Catch    UNKNOWN (missing value)
    Catch    UNKNOWN (missing value)
Internet Plug-ins: ℹ️
    AdobePDFViewerNPAPI: Version: 10.1.12 Support
    FlashPlayer-10.6: Version: 14.0.0.176 - SDK 10.6 Support
    AdobePDFViewer: Version: 10.1.12 Support
    Flash Player: Version: 14.0.0.176 - SDK 10.6 Mismatch! Adobe recommends 15.0.0.189
    QuickTime Plugin: Version: 7.7.3
    Default Browser: Version: 600 - SDK 10.10
User Internet Plug-ins: ℹ️
    Picasa: Version: 1.0 - SDK 10.4 Support
Safari Extensions: ℹ️
    AdBlock
    Facebook Cleaner
    Awesome Screenshot
    RSS Menu
3rd Party Preference Panes: ℹ️
    Flash Player  Support
Time Machine: ℹ️
    Auto backup: YES
    Volumes being backed up:
        Macintosh HD: Disk size: 499.25 GB Disk used: 343.24 GB
    Destinations:
        PROMISE PEGASUS [Local]
        Total size: 3.00 TB
        Total number of backups: 131
        Oldest backup: 2013-02-12 01:21:04 +0000
        Last backup: 2014-11-06 10:40:18 +0000
        Size of backup disk: Excellent
            Backup size 3.00 TB > (Disk size 499.25 GB X 3)
Top Processes by CPU: ℹ️
        15%    backupd
        5%    iVI Pro
        3%    Finder
        2%    WindowServer
        2%    firefox
Top Processes by Memory: ℹ️
    515 MB    firefox
    223 MB    mds_stores
    206 MB    iVI Pro
    206 MB    Finder
    172 MB    softwareupdated
Virtual Memory Information: ℹ️
    5.28 GB    Free RAM
    5.26 GB    Active RAM
    4.92 GB    Inactive RAM
    1.73 GB    Wired RAM
    80.28 GB    Page-ins
    8 MB    Page-outs

Answer 1

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.