Laptop and desktop computers are dominated by x86 chips from Intel and AMD, while most modern smartphones and tablets ship with processors based on ARM designs (although the lines are blurring now that ARM-based Chromebooks and Windows PCs are a thing).

But company called SiFive has been working to shake things up for the past few years by designing processors that use open source RISC-V architecture.

RISC-V has been around for less than a decade, and up until now it’s been pretty far behind the competition in terms of performance. But this week SiFive unveiled its new U8-Series chip design which brings a huge performance boost and could result in chips that are competitive with modern ARM-based processors.

The new U8-Series Core IP is the first RISC-V processor to feature superscalar, out-of-order architecture.

SiFive says the first two U8-Series CPU core designs include the SiFive U84, which is a high-performance, energy efficient core for a wide variety of applications, while the SiFive U87 is designed for “vector processing.”

The company isn’t saying much about the U87 yet, but here are a few details about the U84:

  • It’s a 7nm chip.
  • It offers 3.1X better performance than the previous-gen 16nm U74.
  • That’s due to a 2.3X boost in instructions per clock and a 1.4X lift in maximum frequency.
  • SiFive says it can create chips with up to 9 heterogenous CPU cores combining U7 and U8 Series cores in a way that’s similar to ARM’s big.LITTLE designs (or the Sunny Cove + Tremont structure used in Intel’s upcoming Lakefield processor)

SiFive says when compared with an ARM Cortex-A72 CPU core, the U84 should offer 1.5X better performance per watt, and twice the area efficiency (meaning it should take up less physical space).

Of course, Cortex-A72 is a 3-year-old technology at this point, so it’s unclear how the U84 will stack up against the latest ARM designs licensed by chip makers including Apple, Qualcomm, Samsung, and Huawei. But considering the fact that the first Linux-ready RISC-V chip processor was only made available in 2017, it seems like SiFive is making pretty rapid progress.

If you want a deeper dive into what makes the U8-Series processors tick, AnandTech has an in-depth overview of the new technology.

Support Liliputing

Liliputing's primary sources of revenue are advertising and affiliate links (if you click the "Shop" button at the top of the page and buy something on Amazon, for example, we'll get a small commission).

But there are several ways you can support the site directly even if you're using an ad blocker* and hate online shopping.

Contribute to our Patreon campaign


Contribute via PayPal

* If you are using an ad blocker like uBlock Origin and seeing a pop-up message at the bottom of the screen, we have a guide that may help you disable it.

Subscribe to Liliputing via Email

Enter your email address to subscribe to this blog and receive notifications of new posts by email.

Join 9,547 other subscribers

10 replies on “SiFive’s new U8-Series RISC-V chip designs should be competitive with ARM Cortex-A72”

  1. I hope ARM goes away. What a horrible company and a terrible development experience.

  2. If SiFive was also a hardware producer like Western Digital then they could use their own designs and directly save the ARM licencing fees. I see WD as having the ability to undercut SiFive anytime they want as they are internally making low and high performance RISC-V. I would rather buy a design from WD as they already have a similar design in high-volume production.
    Test-chips are one thing, making millions of chips each year is another.

  3. Very misleading, this core has no SIMD function needed to compete with comparable ARM cores on multimedia compute, and the n times better power efficiency figures have very little detail to back them up.

  4. Sounds like cheerleading, it probably is. Architecture isnt silicon. Im waiting or silicon not “pre-chip hype claims” But OK yes proclaimed progress and node bump.

  5. Not having to pay licensing to ARM can help keep their costs down, but they need to be cheaper than the competition that is paying ARM licensing… by a significant amount that will cause companies to want to switch.
    Raspberry Pi and Broadcom keep getting nice performance bumps each year or two… they already have quad a72 boards for $35.

    1. True.
      ARM has seen explosive growth since 2011. I think if RISC-V can emulate some of that success they will be fine. It looks like they’ve caught up to the ARM Cortex A75-A55 performance and power draw.

      However, they still don’t have the module complete or any hardware produced. So unless that happens this is just a hype show for now. I don’t doubt it, but looks like there’s still another year for that, so the market may change.

      On top, they don’t quite have any software made and optimised for it. On top of actual chips, they need to release some Maker Boards like the Raspberry Pi 4/Udoo Bolt V8, and have something’s running on there like RISC OS, Debian, Fedora, SailOS, Android, ChromeOS, or maybe even Windows IoT. Not too sure about Windows 10S or macOS. Then have this in the hands of developers and consumers.

      That still looks like months/years away. Devs can possibly have this in Console Boxes, Laptops, and Phones. Probably 5 years minimum (2025 ?) to see it in a phone.

  6. Nice. ARM and the companies that license it are as bad as Intel. Hoping to see some adoption of application processor class RISC-V SoCs in the future.

    1. IBM should help make this open sourced RISC-V chip succeed. Hell, its in a lot of companies interests to help it succeed.

      Sadly, it wouldn’t help with app developers.

    2. No, there are 3 x86 licenses but hundreds of arm. But yes arm is proprietary. Open chip is misleading as few tools to make them are. & fabs arent cheap.

Comments are closed.