As you may have noticed there was no Nexus hardware announcement at Google I/O and there is still no official word on the Nexus 8 (or 9) tablet. One of the reasons behind is that ART runtime and Android L (Lollipop and Lickerish are our top two codenames ed.) are not ready.
Google is taking an Apple-like approach and showing it to a bunch of developers in the form of an early beta version of Android L and ART runtime. It will take a few more months hardware based on Android L ships.
You might have guessed that Android L is the direct successor to Android 4.4 KitKat and will help further fragment the Android ecosystem. One important part of Android L is the ART Android runtime that will be used to compile Android applications for different platforms. ART lets you compile your Android apps in native codes from ARM architecture to Intel x86. ART still supports good old just in time (JIT) compiling that is used for some applications.
ART speaks 64-bit
The important feature of ART runtime is the 64-bit support, something that will become increasingly important in the future. We expect that the next generation Nexus will come with 64-bit support out of the box, naturally running a 64-bit processor.
Nvidia already said that its Logan Denver 64-bit dual-core processor ships this year, so there is a big chance we will find Logan in the next generation Nexus 8 – 9. Qualcomm should also have its Snapdragon 805 ready by the end of the year, so Qualcomm is in the game, too.
For what it’s worth, 64-bit support is more marketing than anything else. In theory it will a significant boost in performance and significant changes in the way the OS handles stuff internally, but in the short run we don’t expect any spectacular gains. We might see tablets with more than 4GB of RAM, as 32-bit Android is limited to maximum of 4GB but since we are quite happy with 2 to 3 GB today, it won't bring any major gains. However, when the industry transitions to 4K/UHD tablets, 4GB or more memory will be justifiable.
64-bit support - more marketing than necessity
We lived through a 32- to 64-bit transition on desktop and more than 11 years after AMD introduced the Athlon 64, Google Chrome on desktop is still running in 32-bit mode. Servers benefited greatly from the ability to address more than 4GB of memory and our gaming rigs are happy with 16GB of RAM, but other than that, it's hard to prove that 64-bit processors are actually much faster than 32-bit parts in most everyday tasks.
ART is also important as Google will want to get some action in the server market and if they play this well, there might be some servers running operating systems based on Google Android 64-bit, naturally at a later date.