Got a laggy old Nexus 7? Here’s why Android 4.3 will restore its performance.

Don’t upgrade from an old Nexus 7(s goog) to a new one just yet; at least not if your reason for upgrading is because your current tablet has been getting slower over time. Try the Android 4.3 software update first, which is now in the process of rolling out to Nexus devices. It turns out there’s a simple reason why the performance of some of the 2012 Nexus 7 tablets degraded and it can be fixed through software.
Brian Klug of AnandTech confirmed the fix, which is the inclusion and regular scheduling of a specific software command in Android 4.3. The command helps manage and optimize the tablet’s flash memory.

“In our Nexus 7 (2013) review, I talked about how I had confirmed that Android 4.3 onboard the device had enabled support for fstrim, an application which TRIMs blocks not in used by the filesystem. TRIM is essentially the paging channel through which the OS tells an SSD or eMMC controller that a block is no longer in use, and thus ready for garbage collection. This is critical for maintaining performance on the controllers in use across smartphones and tablets and preventing aging-related I/O performance slowdown.”

By invoking the TRIM command on a regular basis, the flash memory inside the Nexus 7 is optimized for input and output. Think of it like the old Disk Defragmenter on Microsoft Windows PCs which cleaned up the file system and put contiguous file bits in order on the hard drive to speed up I/O performance. TRIM isn’t quite the same but the concept is similar.
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Klug says the TRIM command is automatically invoked every 24 hours or so on the Nexus 7 with Android 4.3. It happens when the device is active but not used for an hour during one day’s time and has either 80 percent battery life or is being charged and has at least 30 percent battery life. The maintenance is automatic then, so there’s no user action required.
While this won’t make an old Nexus 7 faster than a new model — this year’s Nexus 7 has double the memory and a faster chip — it should help restore performance in cases where the tablet was slowing down over time. I’ve already read a number of reports online where owners of the 2012 edition are enjoying a faster experience so if you have the old tablet, I’d recommend upgrading to Android 4.3.