The partnership between Intel and SiFive is taking shape. The companies have jointly announced the platform called “Horse Creek”, from which RISC-V processors will emerge from 2022. Intel takes over the production with 7-nanometer technology and provides additional function blocks, such as memory controllers and PCIe ports; SiFive contributes licensable CPU cores. Chip developers can build these components into their systems-on-chip.
The two new Linux-compatible ones form the heart of the Horse Creek platform CPU cores Performance P550 and P270. The former is said to be the fastest RISC-V core to date. The P550 processes 64-bit commands based on the RV64GC command set and uses a 13-stage out-of-order pipeline. SiFive provides four-core clusters in which each CPU core receives 64 KByte level 1 cache and 256 KByte L2 cache and all cores share a common 4 MByte as L3 intermediate buffer.
The P270 is slimmed down to an 8-stage in-order pipeline with 128 KByte L2 cache per core. Chip designers can provide the CPU core with vector extensions for processing 256-bit instructions.
Design help from Intel
Intel not only manufactures the corresponding processors, but also provides design tools as part of the new Integrated Device Manufacturing (IDM) 2.0 manufacturing strategy. Companies can access (DDR) memory and PCI Express interfaces from Intel, among other things. High-performance controllers for PCIe SSDs would therefore be conceivable.
Corresponding RISC-V processors are only a few square millimeters in size and are therefore well suited for the start-up of 7 nm production at Intel, before larger and therefore more error-prone x86 CPUs and other semiconductor components follow – such as Meteor Lake processors. The process has been delayed for years.
Comparison with ARM Cortex-A75
SiFive compares a P550 quad core with ARM’s older smartphone processing core Cortex-A75: Four P550s should occupy less space, but provide more computing power in relation to the space.
SiFive promises around 8.65 points per gigahertz clock frequency in the integer part of the outdated benchmark SPEC CPU2006 (8.65 SPECint2006 / GHz). At 3 GHz, around 26 SPECint2006 points would be expected. A smaller P270 achieves 4.6 points per GHz.
The new one too SiFive-Kern Intelligence X280 With a 512-bit vector extension, the company Tenstorrent wants to build into its AI accelerator. Tenstorrent was best known through its prominent chief technology officer Jim Keller, who already worked as a processor architect for AMD, Intel, Apple and Tesla as well as for DEC in the 1990s.
According to speculation, Intel is considering a takeover of SiFive or a stake.