SiFive has promised the world another HiFive RISC-V development system featuring a 64-bit out-of-order processor for engineers and other curious techies to try out.

Dubbed the HiFive Premier P550 and unveiled in time for the Embedded World conference in Germany this week, this modest computer uses a Chinese system-on-chip powered by four SiFive-designed P550 CPU cores. The P550 sits in the middle of SiFive's Performance family of RISC-V CPU blueprints. SiFive hopes its latest board will help developers consider deploying RISC-V for "AI and other cutting-edge technologies across different market segments."

Silicon Valley-based SiFive already has a P550-powered developer board of sorts: The HiFive Pro P550, which also has a 64-bit out-of-order quad-P550 system-on-chip. However, despite having been announced in January 2023, the Pro P550 is nowhere in sight in terms of general availability - and SiFive's website indicates the hardware remains "scheduled to be available to key partners late 2023, and more broadly early 2024." All of the Pro's documentation and technical details are still "coming soon."

What's a little awkward is that the HiFive Pro P550's system-on-chip was basically Intel's experimental Horse Creek SoC, designed with SiFive and fabbed by the x86 giant on a 7nm process node. To us it looks as though that project didn't pan out as one might hope, leaving SiFive to launch the HiFive Premier P550 using a Chinese system-on-chip rather than an Intel part.

The troubled Xeon titan has had an on-off relationship with RISC-V, giving SiFive and others funding one year, then canceling an RV dev environment the next, then pushing the open ISA with its FPGAs.

If the Premier P550 goes on general sale before the moribund Pro P550, we guess SiFive's claim that the Premier is "the first commercially available out-of-order RISC-V development board" may hold true. That's carefully caveated because, while there are other out-of-order RISC-V cores out there in one form or another, they may not be available on commercialized dev boards specifically built for those chips that people can just buy and play with.

Furthermore, SiFive, which laid off a fifth of its staff toward the end of 2023, claims the Premier "is the highest performance RISC-V development board in the industry" - which may also be true.

The licensable P550 CPU core is an out-of-order design, meaning it can execute software instructions speculatively to boost performance - a technique other processor families have used for ages, though it admittedly left some of them open to data-leaking side channel attacks.

The Premier's cores each have 32KB of L1 data and 32KB of L1 instruction cache, a private 256KB L2 cache, and 4MB of shared L3 cache, and are paired with 16GB of DDR5-6400 DRAM. Assuming the Premier P550 and the Pro P550 share the same CPU architecture, the Premier cores will each sport a triple-issue, 13-stage pipeline, and are said to clock up to 2.4GHz on, say, a 7nm process node. The ISA (RV64GBC) has everything you need to run general computing.

What makes the Premier P550 interesting isn't so much the CPU cores, but everything else around them. At the heart of the Premier board is an EIC7700 system-on-chip from Beijing-based Eswin (aka Yisiwei) that was announced at the end of last month. Eswin was founded in 2016, a year after SiFive, and is run by Wang Dongsheng, who chaired BOE Technology - a supplier of phone and TV displays for the likes of Huawei. Eswin focuses on components for smart and industrial equipment, IoT devices, and mobile gear.

That EIC7700 chip contains a cluster of four SiFive-provided P550 cores, plus an OpenGL ES 3-compatible GPU capable of 3D and 2D acceleration, hardware video encoding and decoding, support for various peripherals, a DSP, and a neural processing unit (aka NPU) that presumably makes up for the lack of vector math extension support in the CPU cores. As you can see from the photo above, the system-on-chip, its RAM and 128GB of eMMC flash storage, and other bits of logic, sit on a daughter module that can be swapped out.

There are various I/O ports, including a PCIe 3 (yes, 3) interface, five USB 3.2 Gen 1 ports, SATA and SD card ports, what looks like HDMI, serial UARTs, and Ethernet networking. It's not far off the Intel-based Pro P550 that was expected to feature, according to SiFive, "16GB DDR5, 2x PCIe expansion slots, 1/10GbE Networking, USB 3, on-board graphics and a remote management ready interface."

The operating system of choice for the Premier P550 is Ubuntu Linux, as SiFive is working with Canonical directly to ensure good support for this silicon on that open source distro. More info is expected to appear here.

The HiFive Premier P550 is slated for a July 2024 launch and - if that pans out - will have a "large-scale deployment" via Arrow Electronics, with no pricing info. Given that SiFive seems to have missed its deadline for the HiFive Pro P550, it is foreseeable something similar might happen this time around - cross your fingers if you want this RISC-V supplier to succeed. ®

https://www.theregister.com//2024/04/09/sifive_riscv_hifive/