Why does my LG G3 with Cyanogenmod 12.1 run so slowly? I own a LG-D855 which I bought refurbished running the bundled modified version of Android that LG provide.

After a few weeks I installed Cyanogenmod 12.1 and since then I've been updating weekly.

When I turn the phone on for the first time it runs very quickly. However after using the phone with a handful of apps for 15 or 30 minutes the whole phone slows down to a crawl.

I've installed an app which stops as many background processes as it can. After running this the phone speeds up again, but soon returns to it's previous state.

I bought an LG G3 as it rated very highly on lists of the best Android phones to buy.

Why am I having these problems? Are these common issues with the LG G3? What can I do to allow my phone to run more quickly?
First of all, G2 should be D80X, the 85X is the G3 line.

I am an owner of G2 on CM12.1, and I never had any problems regarding speed. It was always fluent without any hiccups.


You can try to hibernate apps using Greenify. 
You can rollback to a previous ROM version/nightly because the current may have bugs
Apps that slow down the phone usually also drain the battery more, look for the apps that use the most battery life and uninstall them
You can swipe apps from the recents when you are done using them
Use some tools to help you out like Xposed, CPU Spy and similar to find and eliminate the problem


In the end, there could be also the case that your CPU is maybe downclocked, or some other hardware issue. Anyways, the G2 on CM12.1 should give you excellent overall experiance.