What Nvidia Tegra K1 Means for Mobile (and PC) Gamers

By Wesley Fenlon

A new CPU design and mobile Kepler GPU mean significant power efficiency improvements and increased performance. More importantly, mobile Kepler could be big for gaming hardware.

Nvidia's 2014 refresh of its Tegra system-on-a-chip, announced on the eve of this year's CES, marks some major changes from the Tegras of years past. Tegra K1 succeeds last year's Tegra 4 with a pair of configurations: one a quad-core Cortex-A15 CPU, and the other a custom 64-bit ARMv8 Nvidia CPU. Even more importantly, K1 uses the same architecture of Nvidia's desktop GPUs, and future GPU designs will grow from mobile into desktop hardware. This leaves us with a couple important questions: How big a deal is K1 for mobile users? And how much will it influence the future of Nvidia's desktop graphics cards?

Anandtech's breakdown of Tegra K1 gives us a good overview of the technology. The custom 64-bit Nvidia CPU making its first appearance in K1 is Project Denver, which Nvidia's been working on for years; the company first announced it in 2011. Like previous Tegra SoCs, K1 includes a fifth low-power core for battery saving. Anandtech points out that Cortex-A15 has seen some improvements since last year, primarily in energy efficiency. The move to 28nm and a max clock speed increase from 1.9GHz to 2.3 GHz means the Cortex-A15 version of K1 will be about 20 percent faster than last year's model.

Photo credit: Nvidia.

That's not a significant difference, even if it means some battery life improvements for Tegra devices. The Cortex-based K1 devices will be shipping in the first half of 2014. In the second half of the year, Nvidia plans to roll out Project Denver with dual-core, not quad-core, 64-bit processors. There's no low-power companion core in this configuration. The CPU is clocked at 2.5GHz, which Anandtech believes is to account for some very specialized software designed to make K1 more efficient.

Nvidia hasn't revealed all the details about Project Denver--or most of them, really. Anandtech speculates Nvidia has built a chip capable of out-of-order execution that will make it more power- and performance-efficient, and a lot of that work is done in software. If Denver's design lives up to its potential, it could signal a major shift away from piling on CPU cores in favor of much more powerful dual-core designs, something Apple has likewise done with the iPhone.

Photo credit: Nvidia.

The Denver CPU is new territory for Nvidia, but the changes it's making to its mobile GPUs may be an even bigger deal for anyone who buys Nvidia hardware, be it mobile or PC. "All architectures will start as mobile designs and then be adopted to fit other, higher power segments," writes Anandtech. "Kepler makes the move into mobile largely unchanged. This is a full Kepler implementation with the same size register file, shared L1 and is 100% ISA compatible with its big brother. It turns out that Kepler, as it was originally designed, was pretty good for mobile."

Nvidia called the K1 Kepler GPU a 192-core GPU, which just means it had 192 CUDA cores. For reference, the GTX 780 has 2304 CUDA cores, but you wouldn't call it a 2304 core GPU. Nvidia also claims that their mobile version of Kepler will deliver 1.5x the performance-per-watt of Apple's A7 and the Adreno 330 GPU. And if there's a major advantage to Kepler's mobile miniaturization, it's APIs.

"In one swift move NVIDIA goes from being disappointing in API support to industry leading," Anandtech explains. "Since this is a full Kepler implementation (just a lower power/performing version) Tegra K1 maintains full API compatibility with NVIDIA’s flagship GeForce products. OpenGL ES 3.0 is supported but so are full OpenGL 4.4, DX11 and CUDA 6.0."

Desktop PC users likely have nothing to worry about when it comes to Nvidia GPU architecture--the company isn't going to abandon the high-end market as it designs its GPUs to work well on mobile. But K1 is potentially a very, very big deal when it comes to mobile gaming and living room gaming. Nvidia claims it now delivers enough raw performance with K1 to outperform the Xbox 360 and PlayStation 3. Whether or not that turns out to be completely feasible in practice, Tegra K1 is at least close to that level of performance, making an affordable, mobile-based Steam Machine a likely reality.

"NVIDIA had a port of Serious Sam 3 running on Tegra K1 demo hardware just fine," Anandtech writes. "Any games that are prepped for Steam OS are very easy to port over to Android. Once you make the move to OpenGL, the rest is allegedly fairly simple. The Serious Sam 3 port apparently took a matter of a couple of weeks to get ported over, with the bulk of the effort going into mapping controls to an Android environment."

This video shows off Nvidia and Epic talking about how amazing the K1 will be for mobile gaming. These promises and prototypes rarely end up mirroring the reality of full games on upcoming hardware, but it goes to show how much the gaps between mobile and console and PC continue to narrow.

If Nvidia's got hardware powerful enough to run Xbox 360 games in a smartphone form-factor, small living room boxes may not be far behind. And if easy Android ports convince more developers to support SteamOS, K1 could be a great thing for gamers.