Odds are good that if you buy a high-end Android device in the next few months, it's going to be packing either the Qualcomm Snapdragon 805 or Nvidia Tegra K1 SoC. We're at a pivotal moment in Android hardware as OEMs begin gearing up for the switch to 64-bit architectures, but only one of these chips has a 64-bit option. Let's take a look at where Nvidia and Qualcomm are going with their respective platforms, and whether or not you should hold out for a 64-bit device.
ARM, but not from ARM
The overwhelming majority of computing hardware in Android devices is ARM-based. Intel has successfully muscled its way into the market with updated x86 Atom parts. Android supports x86 and a few OEMs make tablets with Atom, but it's nowhere near as popular as ARM. All throughout the recent history of mobile devices, ARM has been the core architecture, but not all ARM chips are created equal.
When we're talking about ARM SoCs (systems-on-a-chip), we're actually talking about more than the CPU component. There's also the GPU, memory controller, digital signal processor, and more. We'll get to that later--the first point of distinction between the Snapdragon 805 and the Tegra K1 is in the way they implement the ARM architecture.
Chip makers have the option of licensing ARM's Cortex cores and building a chip around them. That's what Samsung and many smaller firms do. Qualcomm has for a long time licensed the ARM instruction set, which is ARMv7 for 32-bit and ARMv8 for 64-bit. These licenses are considerably more expensive than just getting a stock ARM core, but it allows Qualcomm to design its own custom CPU core for SoCs, and that's just what it's been doing ever since its Scorpion core for the original Snapdragon SoC in late 2008.