Encryption is actually slowing Android 5.0 devices down

As alluded to in our Nexus 6 review, our normal storage performance benchmark was no longer giving valid results as of Android 5.0. While Androbench was not a perfect benchmark by any stretch of the imagination, it was a reasonably accurate test of basic storage performance. However, with the Nexus 5 on Android’s developer preview, we saw anywhere between 2-10x improvement to Androbench’s storage performance results with no real basis in reality. It seems that this is because the way that the benchmark was written relied upon another function for timing, which has changed with Android 5.0. While we haven’t talked too much about AndEBench, it has a fully functional storage test that we can compare to our Androbench results. While we’re unsure of the 256K sequential and random read results, it seems that the results are equivalent to Androbench on Android 4.4 when a 1.7x scaling factor is applied. However, AndEBench results should be trustworthy as we saw no difference in results when updating devices from 4.4 to 5.0. In addition, the benchmark itself uses low level operations that shouldn’t be affected by updates to Android.