Arm outs Mali-D71 DPU, targets 4K120 VR hardware

Cambridge-based SoftBank-owned Arm has announced a new graphics processor intellectual property (IP), the Mali-D71, with which it hopes to capture a chunk of the virtual reality market with the promise of 4K resolutions at 120Hz.

Designed to be licensed alongside the company's eponymous Arm central processor IP and formerly codenamed 'Cetus', the Mali-D71 display processing unit (DPU) claims to be a significant improvement over its predecessors in a range of metrics. The overall power draw is reduced by 30 percent, Arm claims, by adding fixed-function application-specific hardware for composition, rotation, scaling, and other common image processing functions, meaning the actual graphics processor portion of the chip doesn't need to get involved. An implementation of the Mali-D71 is also twice as area-efficient as its predecessor, the Mali-DP650, says Arm, thanks to its ability to repurpose otherwise wasted resources for supporting a second display to instead roughly double the performance of a single-display output.

That Arm is targeting mobile and self-contained virtual reality (VR) hardware, though, becomes clear in the next two headline features. A fourfold increase in latency tolerance, brought about by memory subsystem optimisations, allows the display processor to maintain a full buffer for 120 frames per second (120fps) throughput, while a doubling of overall performance allows the IP block to support a 4K resolution display at a full 120fps - both key features for VR headset support.

Other features of the Mali-D71 include high dynamic range (HDR) support with mixed high and standard dynamic range (HDR/SDR) composition for any display, a doubling of supported Android composition layers to eight in single-display mode, and compatibility with Arm's related CoreLink Memory Management Unit 600 (MMU-600) - the latter a required additional component to achieve the promised quadrupling of system bus delays without dropping frames.

Arm has not indicated when the first devices with a Mali-D71 and CoreLink MMU-600 will hit the market, but offers more information on both on its official website.