SiFive announced a pair of new high-performance RISC-V processors aimed at what it calls "next-generation wearables and smart consumer devices." Known as the P670 and P470, the processors offer new features and improved performance compared to previous CPUs based on the popular open-source architecture.
There's support for virtualization, including a separate IOMMU for accelerating virtualized device I/O, and a full out-of-order vector implementation based on the RISC-V Vector v1.0 spec that was ratified last year. The chips claim to be the first on the market to support the new RISC-V vector cryptography extensions. They also exhibit enhanced scalability, with clusters of up to 16 cores able to work together, though the company has talked up 128 cores in the past.
SiFive’s 600-series is performance-focused — the P670’s predecessor the P650 was expected to match the Arm Cortex A-77 for performance — while the 400-series is more of an efficiency chip. The P550 was the chip of choice for Intel’s Horse Creek development board, which paired RISC-V with DDR5 RAM and PCIe 5.0. Intel attempted to buy SiFive for $2 billion this time last year, but the deal fell apart after the companies failed to agree terms.
The P670 is built on a 5nm process and can achieve a maximum clockspeed of more than 3.4GHz. SiFive’s description makes it sound like a P650 with two added vector units, and the new chip aims to beat Arm designs in the performance-per-mm metric that measures the space a chip takes up against its processing capability.
The P470 is designed as a companion chip for the P670, and we expect it to appear in big.LITTLE configurations in exactly the same way Arm chips do in smartphones and tablets. It’s also designed on a 5nm node and hits the same clockspeed as its bigger brother. A P450 also exists, which is a P470 without its single vector unit, and it has been area-optimized to fit in particularly small places.
“The P670 and P470 are specifically designed for and capable of handling the most demanding workloads for wearables and other advanced consumer applications. These new products offer powerful performance and compute density for companies looking to upgrade from legacy ISAs,” said Chris Jones, SiFive VP of product. “We have optimized these new RISC-V Vector enabled products to deliver the performance and efficiency improvements the industry has long been asking for.”
There's no news of when the P670 and P470 will be available, nor which companies will be using them.
