Will a clean install help performance?

I have a Macbook Air 2013 13" which is getting a bit slow. Will a clean install make a difference? And what are important things to think about when doing a clean install (apart from the obvious issue of back up)?

Advice much appreciated.

 

Thanks so much for this. Info from EtreCheck is below, I'm not sure how to interpret it....?

I currently have 42GB free out of 256 storage, 8GB ram. I'm using El Capitan, v. 10.11.6.

On a typical work day I have the following apps running/open: SpiderOak, Mail, MailMate, Word, OmniOutliner, Skim, 1Password, Ulysses, Evernote, Scrivener, TaskPaper, Calendar, TextExpander, Safari, Bookends, DevonThink Sorter, Google Drive, Box, Dropbox, Hazel, Avast, Default Folder X, BetterTouchTool, Yoink, Skype, Alfred.


EtreCheck

Hardware Information:

MacBook Air

MacBook Air - model: MacBookAir6,2

1 1,3 GHz Intel Core i5 CPU: 2 cores

8 GB RAM


Video Information:

Intel HD Graphics 5000 - VRAM: (null)


Audio Plug-ins:

BluetoothAudioPlugIn: Version: 4.4.6

AirPlay: Version: 2.0

AppleAVBAudio: Version: 403.4

iSightAudio: Version: 7.7.3


Startup Items:

tap - Path: /Library/StartupItems/tap

tun - Path: /Library/StartupItems/tun


System Software:

OS X 10.11.6 (15G1217) - Uptime: 10 days 21:42:22


Disk Information:

APPLE SSD SD0256F disk0 : (251 GB)

EFI (disk0s1) <not mounted>: 209,7 MB

disk0s2 (disk0s2) <not mounted>: 250,14 GB

Recovery HD (disk0s3) <not mounted>: 650 MB


USB Information:

Apple Inc. BRCM20702 Hub

Apple Inc. Bluetooth USB Host Controller


FireWire Information:


Thunderbolt Information:

Apple Inc. thunderbolt_bus


Kernel Extensions:

com.avast.PacketForwarder (2.1)

com.avast.FileShield (3.0.0)


Problem System Launch Daemons:

[failed] com.apple.logd.plist

[loaded] org.postfix.newaliases.plist


Problem System Launch Agents:


Launch Daemons:

[loaded] com.adobe.ARMDC.Communicator.plist

[loaded] com.adobe.ARMDC.SMJobBlessHelper.plist

[failed] com.adobe.fpsaud.plist

[loaded] com.avast.init.plist

[loaded] com.avast.secureline.init.plist

[loaded] com.avast.secureline.uninstall.plist

[loaded] com.avast.secureline.update.plist

[loaded] com.avast.uninstall.plist

[loaded] com.avast.update.plist

[loaded] com.bombich.ccc.plist

[loaded] com.bombich.ccchelper.plist

[loaded] com.google.keystone.daemon.plist

[loaded] com.microsoft.autoupdate.helper.plist

[loaded] com.microsoft.office.licensing.helper.plist

[loaded] com.microsoft.office.licensingV2.helper.plist

[loaded] com.sparklabs.ViscosityHelper.plist

[loaded] com.wuala.WualaFS.KextLoaderHelper.plist

[loaded] org.gpgtools.gpgmail.patch-uuid.plist

[loaded] org.macosforge.xquartz.privileged_startx.plist


Launch Agents:

[not loaded] com.adobe.AAM.Updater-1.0.plist

[failed] com.adobe.AdobeCreativeCloud.plist

[failed] com.adobe.ARMDCHelper.cc24aef4a1b90ed56a725c38014c95072f92651fb65e1bf9c8e43c37a23d420d.plist

[loaded] com.avast.secureline.update-agent.plist

[loaded] com.avast.secureline.userinit.plist

[loaded] com.avast.update-agent.plist

[loaded] com.avast.userinit.plist

[loaded] com.citrix.AuthManager_Mac.plist

[loaded] com.citrix.ReceiverHelper.plist

[loaded] com.citrix.ServiceRecords.plist

[loaded] com.google.keystone.agent.plist

[loaded] com.logitech.manager.daemon.plist

[not loaded] com.sony.ReaderDesktop.RunReaderDesktop.plist

[loaded] net.culater.SIMBL.Agent.plist

[loaded] org.gpgtools.gpgmail.enable-bundles.plist

[loaded] org.gpgtools.gpgmail.patch-uuid-user.plist

[loaded] org.gpgtools.Libmacgpg.xpc.plist

[loaded] org.gpgtools.macgpg2.fix.plist

[loaded] org.gpgtools.macgpg2.shutdown-gpg-agent.plist

[loaded] org.gpgtools.updater.plist

[loaded] org.macosforge.xquartz.startx.plist


User Launch Agents:

[loaded] com.adobe.ARM.[...].plist

[loaded] com.akamai.single-user-client.plist

[failed] com.apple.CSConfigDotMacCert-hege.hermansen@me.com-SharedServices.Agent.plist

[loaded] com.avast.home.userinit.plist

[not loaded] com.avast.secureline.home.userinit.plist

[loaded] com.dropbox.DropboxMacUpdate.agent.plist

[failed] com.google.GoogleContactSyncAgent.plist

[not loaded] com.tidal.desktop.plist

[failed] com.wondershare.mobilegodaemon.plist


User Login Items:

Box Sync

SMS+

Citations

Default Folder X Helper

DEVONthink Personal Sorter

BetterTouchTool (215)

Alfred

BetterTouchTool

AdobeResourceSynchronizer

Dropbox

HazelHelper

NoteBookHelper

SpyderUtility

readerAppHelper

SpiderOak

CCC User Agent

Google Drive

TotalFinder

AdobeResourceSynchronizer

Jottacloud

Default Folder X

SpiderOakONE

MEGAsync

AirDisplayStatusItem

Air Display

DEVONthink Sorter

Box Edit

Box Local Com Server

HazelHelper


3rd Party Preference Panes:

Air Display Preferences

Akamai NetSession Preferences

Citrix ShareFile Sync

Flash Player

GPGPreferences

Growl

Hazel

Java

Logitech Preference Manager

MacFUSE (Tuxera)

TeXDistPrefPane

Tuxera NTFS


Internet Plug-ins:

AdobeAAMDetect.plugin

AdobePDFViewer.plugin

AdobePDFViewerNPAPI.plugin

CitrixICAClientPlugIn.plugin

Default Browser.plugin

DirectorShockwave.plugin

QuickTime Plugin.plugin

Flash Player.plugin

FlashPlayer-10.6.plugin

JavaAppletPlugin.plugin

MeetingJoinPlugin.plugin

SharePointBrowserPlugin.plugin

Silverlight.plugin


User Internet Plug-ins:


Bad Fonts:

None


Time Machine:

Skip System Files: NO

Mobile backups: OFF

Auto backup: YES

Volumes being backed up:

Destinations:

Untitled [Local] (Last used)

Total size: 499,73 GB

Total number of backups: 21

Oldest backup: 2016-01-27 16:20:07 +0000

Last backup: 2016-11-15 15:34:39 +0000

Size of backup disk: Excellent

Backup size 499,73 GB > (Disk size Zero KB X 3)


Top Processes by CPU:

20% WindowServer

12% firefox

7% Safari

3% Box Sync Monitor

2% hidd

1% Calendar

1% Box Sync

1% EtreCheck

1% Google Drive

0% com.apple.WebKit.Networking


Top Processes by Memory:

934 MB Safari

590 MB firefox

164 MB Mail

131 MB suggestd

98 MB plugin-container

82 MB WindowServer

82 MB Calendar

82 MB mds_stores

74 MB Skype

57 MB com.apple.WebKit.WebContent


Virtual Memory Statistics:

77 MB Free RAM

2.29 GB Active RAM

2.15 GB Inactive RAM

1.82 GB Wired RAM

55.34 GB Page-ins

2.98 GB Page-outs

 

Awesome, thanks so much, everybody. I did a safe mode restart and there was a MASSIVE difference. So taking my cue from this...

...I've been deleting just about everything in those folders, including the tap & tun as it's not needed for my current VPN, and cleaned up the list of apps that start on log in. After a re-start, it all seems a whole lot better - that's just a first impression at the moment, but looks positive.

Thanks a lot