The Jetson TK1 SOC
The Tegra K1 SOC in the Jetson TK1 is targeted for embedded GPGPU applications as well as general purpose use in power-constrained devices such as super-phones, tablets, laptops, set-top boxes, and low-power desktop computers.
The Tegra K1 SOC GPU provides excellent GPGPU performance per Watt. Nvidia claims Tegra TK1 can attain 326 GFLOPS, whereas its closest contemporary competitor, the SnapDragon 805, may achieve estimated 200 GFLOPS. Imagination Technologies announced a PowerVR GX6650 design which they claim can challenge the Tegra K1 performance. However, the design favors FP16 operations which may limit its usefulness for GPGPU tasks. As of June 20 2014, public bench marks are not available, and the GX6650 may not ship to consumer until 2015. By that time, the NVidia Erista (the Maxwell successor to the Tegra K1) should be available.
NVidia leapt over the competition by using the same Kepler GPU architecture that it has used for years to power the worlds fastest desktop GPUs and super computers. This decision allows them to offer existing, well-tested tools on the TK1 with minimal modification. Supported APIs include OpenGL ES 3.0 and OpenGL 4.4, DirectX 11, CUDA 6, and OpenCL 1.2.
In my testing, GPGPU tasks have required the highest power draw by a wide margin. Typical non-GPGPU applications, including demanding OpenGL games, rarely required more than 5W for the SOC + RAM. GPGPU applications that harnessed the power of all CUDA cores, however, could push the SOC + RAM numbers to 9W.
Frames Per Seconds (FPS) Comparisons
The Jetson TK1 provides a relatively unique combination of hardware and software. The CPU is ARM architecture, the GPU is NVidia Kepler, and the OS is Ubuntu Linux 14.04. While this a fine software stack, it is also unique. As a result, has proved more difficult to compare graphic performance with a traditional x86 stack.
Testing shows graphics performance on the Jeston TK1 to be roughly comparable to Intel HD 4600 graphics, but with superior OpenGL and GPGPU capabilities.
Power Use - Overview
Power draw for graphic-intensive tasks has been surprisingly low perhaps because the default to lower-power FP16 operations. GPGPU tasks generally require more power.
- Standard Jetson TK1 developer board
- Audio out active
- Attached GbE
- One NFS mount to external NAS active
- Four port USB3 hub attached
- Logitech K310 USB Keyboard attached via USB hub
- Logitech Marble Mouse attached via USB hub
- Logitech C615 HD video cam attached via USB hub
- HDMI out @1920x1080
- Standard Cooling Fan
- Installed 64GB SD card with one ext4 mount active
- Kubuntu standard desktop, compositing disabled
The Jetson TK1 was tested in a response to a forum discussion. I tested using a Multimeter patched into the DC line between the A/C power converter and the board.
- The power adapter was measured to provide consistent 12.15 volts.
- The fan's power draw (0.85W) was determined by unplugging it for a short time while the board was idle and noting the difference in power draw.
- The Jetson TK1 board as configured has yet to exceed 12.0W total draw under any workload tested.
- Nvidia's numbers found in their brief (page 13) appear accurate to conservative.
- Nvidia's point about drawing comparisons to mobile appear valid. The board drives a number of ports that either have low-power alternatives or aren't normally available mobile devices. Examples include GbE, desktop RAM, the SATA port, and mini-PCI.
- The system as configured draws about 2.0W with the processor running at ~0.6W at idle.