Microsoft Reveals Holographic Processing Unit Chip

Microsoft reveals the first look at the inside of its Holographic Processing Unit (HPU) chip, which is used in its virtual reality HoloLens specs.
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According to, the secretive HPU is a custom designed TSMC fabricated 28nm co-processor, which has 24 TensilicaDSP cores, which has been arranged in 12 clusters. It has about 65 million logic gates, 8MB of SRAM along with a layer of 1GB low-power DDR3 RAM on top, all in 12mm by 12mm BGA package.
It would handle all the environment sensing and other input along with the output necessary for virtual-reality googles. It aggregates data from the sensors and processes the wearer to gesture movements in hardware. Hence, it is faster compared to the equivalent code, which is running on a general purpose CPU. Each DSP core has been provided with a particular task to focus on.
The unit resides alongside a 14nm Intel Atom x 86 Cherry Trail systems-on-chip, which comes with its own 1GB RAM and runs on Windows 10. The apps take advantage of the immersive noggin-fitted display.
The details have been revealed at the Hot Chips conference in Cupertino, California.
The HPU draws less than 10W and goes on to include PCle, as well as the standard serial interfaces. Microsoft has taken advantage of Tensilica’s instruction extensions, so as to add 10 custom instructions to the DSPs, speeding up the specific operations, which are required by HoloLens, so as to render real time augmented reality. The entire unit is quite capable of accelerating the algorithms to 200 times faster, compared to it being used in pure software.
Data shuttled over to host the Atom processor is quite possible, meaning that x86 CPU should not need to do numerous extra processing work on the information taken from the HPU.
The slides and information have been revealed by Microsoft Devices Group engineer Nick Baker, who went on to state that Redmond had rejected the use of traditional CPUs or CPU-GPU SoCs in favor of a bespoke design, which goes on to include the hardware acceleration and the programmable elements. None of the DSP cores are pushed beyond 50 percent capacity for now. The HPU’s design now allows Microsoft’s engineers to guarantee latency as well as duty cycles while processing.
HoloLens had initiated shipping to the developers in March and by next year Windows 10 PCs will be able to use it, so as to provide a 3D desktop environment.