Operating system: Linux 4 Tegra (Ubuntu 14.04)
Processor: Nvidia Tegra K1, quad-core 2.3GHz ARM Cortex-A15 plus ‘Shadow Core’
Graphics: 192 Kepler CUDA cores, 852MHz
Memory: 2GB DDR3L 933MHz RAM, 4MB ROM
Storage: 16GB NAND Flash (expandable via SD Card)
Connectivity: Realtek RTL8111GS 10/100/1000 Ethernet
Ports: 1x RS232, 1x HDMI, 1x USB 3.0, 1x microUSB 2.0, 1x Ethernet, 1x analogue audio out, 1x analogue audio in, 1x SATA with four-pin power, 1x JTAG, 125x GPIO, 1x single-lane mini-PCI Express slot
Dimensions: 133mm x 133mm x 30mm
Weight: 120g (excluding PSU)
The Jetson TK1, Nvidia’s first development board to be marketed at the general public, has taken a circuitous route to our shores. Unveiled at the company’s Graphics Technology Conference earlier this year, the board launched in the US at a headline-grabbing price of $192 but its international release was hampered by export regulations. Zotac, already an Nvidia partner for its graphics hardware, volunteered to sort things out and has partnered with Maplin to bring the board to the UK.
In doing so, however, the price has become a little muddled. $192 – a clever dollar per GPU core – has become £199.99. Compared to Maplin’s other single-board computer, the sub-£30 Raspberry Pi, it’s a high-end item that could find itself priced out of the reach of the company’s usual customers.
A glance at the specifications reveals why the Jetson is so highly priced: its heart is the latest-generation Tegra K1 processor, a 32-bit ARM Cortex-A15 implementation which packs four 2.3GHz CPU cores and a fifth low-power ‘Shadow Core’ that takes over during background processing to reduce average power draw. Its biggest feature, however, is the chip’s 192 Kepler GPU cores, based on the same technology as Nvidia’s desktop and laptop graphics chips and boasting full support for the Compute Unified Device Architecture (CUDA) general-purpose GPU offload language.
Using CUDA, developers are able to take tasks that are highly parallel in nature and run them on the GPU cores rather than the CPU. It’s a technique that is well-used in supercomputing, but that can accelerate everything from cryptography to computer vision. It’s also the only GPGPU language supported by the Jetson: despite the Tegra K1 itself boasting fully certified OpenCL support, this is not implemented in the Jetson, leaving Nvidia’s proprietary CUDA as the only option available to developers.
Another odd restriction comes in the choice of operating systems available. The Jetson comes with Linux 4 Tegra, a modified version of Canonical’s Ubuntu 14.04, loaded into NAND flash. This is the only operating system supported, with Google’s Android – the most common software used on the Tegra K1 processor – nowhere to be seen.
If being restricted running CUDA on Ubuntu is no barrier, developers will find the Jetson a powerful device. During testing, the board completed the SysBench single-threaded benchmark with a 95th percentile time of 7.31ms – far faster than any other single-board computer we’ve ever tested, including the Intel Atom-powered Minnowboard and AMD APU-based Gizmo, and a far cry from the 51.45ms of the Raspberry Pi. For tasks that can be ported to CUDA, there’s a total of 300 gigaflops of single-precision floating-point performance on offer from the GPU – and all accessible in an average power draw of 7W and peak of 14W, with the board sitting at around 3W idle during testing.
As well as CUDA offload, the GPU can also be used as a standard graphics processor. Running the Nexuiz first-person shooter at a 1280×720 resolution with all graphical settings turned to max saw the Jetson barely break a sweat, with an impressive 6W peak power draw.
It’s unlikely anyone will be gaming on the Jetson, though. For hobbyists, its 125 general-purpose input-output (GPIO) pins will be the real draw – but there’s a catch: only seven pins are available for true GPIO use as standard, with a few more available when the second camera channel is not in use. The remainder are reserved for uses like flat-panel displays, touch sensors and cameras. Coupled with uncommon 2mm pin spacing, and the use of 1.8V logic rather than the more popular 3.3V or 5V, it makes using the Jetson’s GPIO in hobbyist projects awkward at best.
There’s no denying that the Jetson TK1 is one of the most powerful single-board computers on the market, and having a familiar Ubuntu-based operating system preloaded in NAND is welcome. Its high price and hobbyist-unfriendly GPIO, coupled with perplexing lack of OpenCL support, sadly, keep it from being a device for everyone.