This app can solve your Android device's lag by "trimming" NAND storage [root]17
When one deletes a file, the chip doesn't outright delete the information, but merely marks the sectors that file occupied as "not in use" and available for overwriting with new data. Both the data and the file system entry stay there, which means that, as you go on writing and deleting files, the file map grows increasingly bigger and the controller takes longer to discover the data that you're looking for among all the redundant entries. This leads to the appearance of lag, which grows increasingly noticeable during the device's lifetime, unless there is TRIM support available in its operating system.
The original Nexus 7 (2012), for example, was notable for slowing down to a frustrating state as days of usage went by, the lack of TRIM support being the culprit. TRIM basically goes through the file map and tells the NAND controller to stop tracking sectors marked as "not in use". Thus, deleted files are no longer being tracked, which removes overhead and noticeably speeds up searching. Alas, Google introduced TRIM support in Android 4.3, relatively late in the operating system's lifetime, which left older devices susceptible to the woes of non-TRIMmed flash memory. But that was long ago.
However, no TRIM support is perfect, and neither is Android's. The program might simply take too long between instances of wading through all the redundant entries in your file system, which means your device may not always be as snappy as you want it to be. In such cases, rooted users can use apps like Trimmer to initiate a manual NAND trim if they feel their devices have become slower than normal. Trimming often should keep NAND performance at near peak levels, and your smartphone or tablet will appear as springy as possible.
Trimmer is very simple to use, and is also free and ad-free. If you have a 2012 Nexus 7 running Android 4.3 and beyond, feel free to give it a try and see it goes, you might end up pleasantly surprised!
|Developer: AdminseHow||Download: Android|
|Category: Tools||Price: Free (with in-app purchases)|