A complaint about the Nexus 7 is, without a doubt, the fact that the device is getting slow according to the time of use, I can say that, because I have the 1st generation of Google tablet for a few months. The good news is that with the update of Android to 4.3, Google implemented a command capable of preventing the slowness of the Nexus 7 operating system. So, the owners of the first Big G tablet are well off with that!
According to the Android Authority, the reasons why Nexus 7 presents this problem are related to the low level of the software, specifically the way in which the information is written to the tablet’s flash memory. While the data blocks that make up the storage were empty (when the tablet is new), data recording was fast and the operating system ran smoothly. With the storage space full, the operating system keeps looking for free data blocks to use, this goes very well until all the used blocks are full, so the operating system has to delete blocks before writing them and this causes to the tablet an almost dramatic slowness.
The solution is for the operating system to periodically issue a command TRIM, which checks each block of data that is no longer in use and clears it. In this way, when data needs to be written to flash storage, empty blocks will be available.
It turns out that TRIM does not work on the Nexus 7 running on Android 4.2, which explains why many users have been experiencing performance issues. However, the Nexus 7 running on Android 4.3 supports this command. So, in addition to Nexus 7 (2013) not having this problem, and Nexus 7 (2012) should work better after upgrading to Android 4.3.
According to Brian Klug, from AnandTech, Android 4.3 will run the «fstrim» command daily, ensuring that this cleaning to offer space is constantly on the Nexus 7. As the command will run under certain circumstances – when the device is inactive, with the screen off and the battery over 70% – once your device is updated, it will take some time for you to notice the difference in tablet performance.
Although Google is bringing the improvement now, there were already solutions available to issue the TRIM command on devices such as the rooted Nexus 7, such as LagFix.