Android (rooted): One of the biggest issues with Android is lag -- simple delays that make launching apps and returning to the home screen take a little longer than they probably should. XDA developer lambgx02 decided to tackle the issue and came up with a simple app that can seriously decrease the lag you experience with your Android.
The issue Seeder addresses is that Android draws from a predefined entropy pool -- or set of random data -- for almost all of its operations. When that limited pool of random data dries up, it has to rebuild itself, which results in delays while apps and services wait for the data they need.
Seeder takes the process that generates this data and runs it every second (it's extremely light on resources -- this usually happens behind the scenes anyway, so you don't notice it), then feeds that information to a new random data pool that's constantly kept refreshed. Then, the app uses that fresh data to "top off" the system pool so it never runs out. That means you never have to wait for the generation service to start up and fill the pool with random data. The result? Almost everything about your Android phone is several times faster.
We're simplifying the issue here, so if you're interested in the guts of how this works, dig into the XDA and Reddit threads linked below. We tested Seeder on a few Android devices, and found notable performance improvements on both newer and older Android phones (my OG Droid specifically was much faster while Seeder was running.) As with all apps of this type, your mileage may vary, but we saw good results, as have many posters at XDA and Reddit.
There is some controversy though -- the issue was reported to Google's Android dev team, and they've summarily dismissed Seeder as a placebo. They're still investigating and working with other devs on it though, so we haven't seen the end of this. With that in mind, the app is available for free at the XDA thread below, but you have to be a member to download it. If you're not, sign-ups are free.
The dev does have a $US1.49 version of the app at Google Play, which is exactly the same as the free one, but you get automatic updates as they're released.
[APK] Seeder entropy generator to provide significant lag reduction [xda-developers via Reddit: /r/Android]