AMD’s “Zen” Integrated Chipset Having USB 3.1 Issues

AMD is changing things up with its next-generation processors and APUs based on the “Zen” micro-architecture. They will be integrating the chipset into the processor / APU die, which will make motherboards completely chipset free. According to rumors this on-die chipset is facing issues with its integrated USB 3.1 controllers. AMD has sourced the design for the integrated USB 3.1 controllers from ASMedia. ASMedia has a tendency of sourcing its integrated controller IP from third-party manufactures, for example in the past its SATA controllers and port-multipliers have been sourced from Silicon Image.

In any case motherboard manufacturers are experiencing a significant drop in USB 3.1 bandwidth because of the increase in circuit distances. To give you an idea think of wiring from the AM4 socket to USB 3.1 front panel headers on the bottom right corner of a motherboard. Board designers are said to have had to use additional retimer and redriver chips to get acceptable bandwidths over these ports, and in some cases even entire USB 3.1 controllers. This eats up the platform’s PCIe budget and adds to the cost.

AMD has stated that the “Zen” platform is on-track, and that they will not comment on “customer specific board-level solutions.” ASMedia played down the report as industry rumors and has said that its solution has passed the necessary certifications.

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