Brit chip designer Imagination Technologies today debuts its APXM-6200 RISC-V CPU cores, aimed at powering smart TVs, wearables, Internet of Things, embedded hardware, and similar gear.

Imagination's latest blueprints are another challenger in the arena of licensable CPU cores for system-on-chip (SoC) designs, an area dominated by Arm. However, RISC-V CPU designers like SiFive and Imagination have been slowly turning up the heat. Imagination looks to continue that trend with its APXM-6200 CPUs, which are the third version it has made and the second to be licensed.

The APXM-6200 core uses a 64-bit in-order implementation of the RISC-V architecture with an 11-stage pipeline, and is designed to be Linux and Android-ready. CPU designs utilizing APXM-6200 cores technically cap out at four cores total, but Imagination told The Register that 8 and 12-core designs are possible and customers could ask for them. However, only the single, dual, and quad core designs are actually validated thus far.

APXM-6200 cores are designed similarly to Arm's Cortex-A series. Its 11-stage pipeline is a little longer than the eight-stage pipeline for cores like the popular Cortex-A53, though is a little leaner on the cache compared to more recent Cortex-A cores, with up to 128 KB L1 and 1 MB L2 per core, with no option for L3 cache.

Despite the overall similarities, Imagination says it has got Arm's most popular cores on the run. In SpecINT2k6, APXM-6200 cores apparently beat out the popular but aging Cortex-A53 core by 65 percent. Imagination also claims a 38 percent lead over the Cortex-A55 and a 14 percent advantage against the Cortex-A510.

What Imagination really prioritizes with APXM-6200 is performance density, however. It claims the APXM-6200 core has 2.5 greater performance density than the Cortex-A53, thanks to being both 25 percent smaller and 65 percent faster. As more recent Arm cores have boosted performance at the cost of area efficiency, the APXM-6200 boasts 2.8 times the density of the Cortex-A55 and 3.4 times that of the Cortex-A510.

While Cortex-A cores are used for all sorts of things, Imagination is pushing smart devices like smart TVs, wearables, and speakers as potential use cases for APXM-6200 cores. The 128-bit vector registers on APXM-6200 cores could also be utilized for AI-focused applications like robotics, and there's even an option to add on AI accelerators to APXM-6200 CPU designs. These accelerators can even come from third parties.

Imagination also talks up its GPU IP, which was validated for RISC-V a couple of years ago. APXM-6200 SoCs can come with Imagination graphics as well. Being a one-stop shop for both CPU and GPU cores is certainly an advantage, as Arm and AMD know very well. Not to mention that Imagination is perhaps the most notable RISC-V firm to have its own graphics technology.

"When it comes to a widely adopted GPU with strong ecosystem support and full functionality for both 3D graphics and compute, along with comprehensive support for Khronos standard APIs such as Vulcan, Open GLES, and OpenCL, we can confidently assert that we are the only GPUs for the RISC-V world," Imagination told the Register.

The inclusion of Imagination graphics could come in handy for a variety of things, including AI. Imagination sees its GPU technology as augmenting AI performance in a flexible way, and for chip designers wanting to get more out of processor with APXM-6200 cores, adding in Imagination graphics could be an option.

Still, we're probably not going to see high-end AI-focused processors made using APXM-6200 cores, as Imagination told us, though it's not certain a customer won't design such a processor using the APXM-6200 core at some point. However, we do notice a "high performance application CPU" on Imagination's roadmap, which may fill a similar role to SiFive's RISC-V-powered P870 cores for AI.

"We have a robust roadmap for both GPUs and CPUs aimed at delivering a more efficient, high-performance, and flexible AI solution tailored for edge applications," Imagination said, a hint that the company may expand its horizons down the line.

Imagination tells us that we can probably expect CPUs using APXM-6200 cores to arrive in the second half of next year, perhaps closer to the end of the year, and will be working with its partners starting in the summer to get these chips to market. ®

https://www.theregister.com//2024/04/08/imagination_riscv_cpu_cores/