Optimize Blender's user interface for performance As a simply a Blender hobbyist, I can't justify the an upgrade  to improve the performance of my computer. I wondered, "What could I do that I'm not already doing that could make Blender run faster?" I realized that lowering quality settings in the UI could help lighten the load on my machine. 

What GUI settings, preferences, or add-ons are there to help optimize Blender's performance?

I realize that changes like these could have only a trivial effect on overall performance, but I'm really wanting to squeeze every last drop of computational power out of my machine.

I'm looking for optimizations of any sort, including GPU performance, CPU performance, and memory efficiency.

Thanks for your time!
In The System tab of User Preferences goto Opensubdiv Compute and try using OpenMP or CPU.

Also on that same tab, scroll to the bottom and increase your Memory Cache limit. It should be set to 1024 by default. If you have 8gb of ram, then click that box and type *7 after the number 1024 (so 1024*7) which equals 7168, which means that blender will use 7 of the 8gb of RAM for memory. Be careful and play around with this value, try to stay in multiples of 1 so you use 1, 2, 3, 4 ect GB of RAM.

To better fine tune blender to your machine, read up on the settings available to you in the user manual.
https://docs.blender.org/manual/en/dev/preferences/index.html

I would suggest working in blender internal, as this side of blender is not so resource intensive. You may also want to work on low poly projects. This will also help you with modeling.
However, if you would like to speed up renders in cycles, take a look at this video: 18 Ways to Speed Up Blender Cycles Rendering - https://www.google.com/url?sa=t&amp;rct=j&amp;q=&amp;esrc=s&amp;source=web&amp;cd=2&amp;cad=rja&amp;uact=8&amp;ved=0ahUKEwiGiNO38abbAhVhITQIHcloBGAQFggxMAE&amp;url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3D8gSyEpt4-60&amp;usg=AOvVaw2jR9KDsJDWUto-lZ-N4csG

You could also optimize your windows start up by removing things that you don't need to start when your computer boots up. De-fragment, and uninstall any programs that you don't use anymore. Aside from that, I do not believe there is much you can do without upgrading your hardware.

You can also render files without blender open, to my understanding, from the command line. There are several tutorials on youtube about this. And even addons to use for this purpose.