Regardless of the differences, the Nexus 7 used trim (introduced in Android 4.3) on it&#x27;s flash-based (SSD also uses flash) solid-state memory and my Nexus 9 does not. The trim &quot;bug&quot; is well known for some Android devices, but now it has died off. I was attempting to guess why.<p>Another quick Googling seems to say improved garbage collection (in the SSD itself) has lessened the need for fstrim.<p>Hopefully someone who is knowledgeable will chime in.