Disabling pretty and automatic:
Disabling “eye candy” such as Transparency and turning off automated features such as Widgets will improve Yosemite performance.
Go into the Apple Menu, select System Preferences, and click on Accessibility.
In the Accessibility window check the Reduce Transparency box.
Change Minimize Windows to Scale:
Any effect that is used when minimizing windows unnecessarily consumes system resources.
Go into the Apple Menu, select System Preferences, and click on Dock. Change the Minimize windows from Genie effect to Scale effect.
Uncheck the Animate opening applications box. You can check or uncheck any of these features. Remember: less is more.
Widgets are cool looking and convenient, but they use quite a bit of system resources. Not updating Widgets significantly speeds up rebooting and improves performance. Click on the Widgets toggle in the upper right corner.
Uncheck, deactivate, and remove as many items as possible from both the Today and the Notifications panels.
Disable the Extensions that you don’t need:
Go into the Apple Menu, select System Preferences, and click on Extension.
Go to the Today options in the left column and uncheck any or all extensions you don’t require.
Disable sleep, Power Nap, and screen saver:
Go into the Apple Menu, select System Preferences, and click on Energy Saver.
Uncheck everything except Prevent computer from sleeping automatically and Start up automatically after a power failure. Move the Turn display off after slider to the far left set to Never.
Go into the Apple Menu, select System Preferences, and click on Notifications.
In the left column click on and highlight the Do not disturb option and uncheck as many boxes as possible.
In the left column click on and highlight each of the features (Calendar, Face Time, Mail, Messages, etc) and uncheck as many boxes as possible. Change to 1 recent item for each feature.
Speed up new Finder window generation:
In the Finder pull down menu select Preferences.
Set the New Finder windows show to the place you go to most often. This could be Desktop, Documents, Music or your user home folder.
Removing unused languages:
Go into the Apple Menu, select System Preferences, and click on Languages & Region.
Make certain that only the language(s) you use are listed. Highlight and delete unused languages and add any languages you may need using the + and – buttons.
Removing the presentation order for Spotlight:
Go into the Apple Menu, select System Preferences, and click on Spotlight.
In the Spotlight control window select the Search Results tab.
You’ll see a list of Applications with check boxes next to them. Uncheck all of the boxes. There is no point to even leave “Music” for a server because your library/player software doesn’t access through Spotlight.
Disabling Login Items:
Ideally you want only one Application to automatically open when you login to your computer. If you use your Mac as a dedicated music server you would only want to open your player software at Login. If you were a professional, you would want your accounting software, CAD software, etc. to automatically open at Login. At the same time, you want to disable any other applications that may automatically want to open at Login.
Go into the Apple Menu, select System Preferences, and click on Users & Groups. To streamline the Login items click on the Login Items tab at the top.
Note: this is the same window you can add guests and users with restricted access. For example, you could allow your children to log on to your media server and play recordings from your NAS drive, but not have access to change any of your administrative settings.
You’ll see all the Applications you’ve set to automatically open at Login in the main window. You can remove any optional automated fluff Apps, such as iTunes Helper, to improve system performance.
I recommended that you upgrade iTunes with a high-performance music/media player Application.
Disabling Automatic Software Update:
Go into the Apple Menu, select System Preferences, and click on App Store. Uncheck the Automatic Updates box.
Note: this is the same place you can manually check for updates.
I can not recommend more strongly that before updating you always make and test (yes, test) a backup of your drives.
Often updates have bugs or conflicts with drivers. Having a bootable backup allows you to easily return to your former working system, when as is quite common, an update screws up your computer : P
Repairing disk permissions:
For optimal system performance it is recommended that after you do any OS X updates, Application updates, or transfer large quantities of data, that you Repair Disk Permissions. This is a good habit to get into.
You can find Repair Disk Permissions in your Disk Utility Application.
Activate your Launchpad. Disk Utility is located in your Other folder.
Note: use the Esc key on your keyboard to return from the Other folder to the rest of your Launchpad Applications.
To Repair Disk Permissions simply highlight the disk you want to repair.
When repairing disk permissions is done you will see Permissions repair complete at the bottom of the Show details window.
Disabling the Time Machine automatic backup:
Go into the Apple Menu, select System Preferences, and click on Time Machine.
On the left side of the window, you’ll see a slide selector that has off at one end and on at the other. Make sure the selector is switched off.
Warning! Your drive will inevitably fail: back up often. Using a bootable backup will save you a significant amount of time when you have to reinstall your boot drive.
Disable the automatic journaling feature:
Just as before, launch Disk Utility by activating Launchpad, clicking on the Other folder, and selecting the Disk Utilities icon.
Individually select any drive on the list. Hold down the Option button on your keyboard and click on the File drop-down menu. Slide down the File drop-down menu and select Disable Journaling. If you don’t hold the Option button down while selecting the File drop-down menu, Disable Journaling will not be a selectable option.
Repeat this for all drives.
If you wish to enable the automatic journaling feature for a drive, simply repeat the above process and select Enable Journaling in the same drop-down menu.