Google is all set to replace Dalvik with ART (Android Run Time) in the next version of Android. Whatever lag issues that are present in Android currently can be blamed on the use of Dalvik, which compiles app when they are launched compared to ART pre-compiling apps. Comparisons between ART and Dalvik have shown that the former provides much superior performance in apps including lower load times and smoother animations etc. 

Android SoC vendors like Qualcomm have constantly used some proprietary tweaks to speed up Dalvik runtime on their SoCs, which have helped increase scores in benchmarks dramatically. However, since these optimizations are proprietary (closed source), they are not included in the Nexus devices and cannot be used by developers in custom ROMs, because of variations of OEM skins from stock Android. The lack of Dalvik optimizations is also the key reason why the Nexus devices always scored lower in benchmarks compared to offerings from other OEMs.

However, thanks to the Android 4.4 update for the Moto X, Nexus owners can now also enjoy the goodness of these closed source Dalvik optimizations. A senior XDA member, kszaq, has extracted the Qualcomm-optimized Dalvik libraries from the Moto X KitKat update, and repacked it into a CWM flashable ZIP file for Nexus devices.

Initial reports show that post the installation of the optimized Dalvik libraries, the benchmark scores of the Nexus 4, Nexus 5 and the Nexus 7 jumps up by a pretty huge margin. The improvements in day to day usage, at least on my Nexus 5, are tough to say. The optimized Dalvik libraries should work on any rooted Android device, that is powered by Qualcomm’s Krait processor. Head over to this XDA thread for the download link.

Do drop in a comment and let us know if you noticed any difference after flashing the optimized Dalvik libraries on your Android device!