Testing a Chinese x86 CPU: A Deep Dive into Zen-based Hygon Dhyana Processors

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In 2016, through a series of joint ventures and created companies, AMD licensed the design of its first generation Zen x86 processors to be sold into China. The goal of this was two-fold: China wanted a ‘home grown’ solution for high-performance x86 compute, and AMD at the time needed a cash injection. The outcome of this web of businesses was the Hygon Dhyana range of processors, which ranged from commercial to server use. Due to the Zen 1 design on which it was based, it has been assumed that the performance was in line with Ryzen 1000 and Naples EPYC, and no-one in the west has publicly tested the hardware. Thanks to a collaboration with our friend Wendell Wilson over at YouTube channel Level1Techs, we now have the first full review of the Hygon CPUs.

Let’s Start From The Beginning

There are two/three primary manufacturers of x86 processors: Intel, AMD, and Via/Centaur. Both Intel and AMD have been competing in the high performance compute space for multiple decades, and the reason there hasn’t been any other competitors is due to licensing. Due to patents surrounding the x86 architecture, Intel doesn’t want anyone else coming in and treading on its market share dominance, and to complicate matters, it is AMD’s version of 64-bit x86 that is currently being used by all involved. Intel and AMD are inextricably linked in this way. Meanwhile. Via/Centaur is along for the ride, with a very small market share mostly in Asia, and a lack of a leading edge high performance competitor.

For those who haven’t been following AMD, the company has been through a number of ups and downs. A significant down was during its Bulldozer CPU architecture years, where costs were high, performance wasn’t great, and Intel pulled ahead significantly in all areas: laptop, desktop, commercial, and enterprise. The design of Intel’s CPUs and its market dominance strategy, combined with the lack of a leading edge competitive product for AMD along with the purchase of graphics IP company ATI, nearly bankrupted AMD. Through the leadership of the former CEO, Rory Read, AMD became stable, and under the auspices of current CEO Dr. Lisa Su, the company put heavy investment back into its x86 CPU design. At one point, AMD’s debt was higher than its tangible assets, and the company had to even sell its headquarters and lease the buildings back from the new owners to find the funds to stay afloat.

Another element of this ‘staying alive’ tactic was the sublicensing of AMD’s x86 IP, which ultimately created the Hygon Dhyana x86 processors for China. Some people will quote this as being a keystone for AMD staying alive, however it is of a general consensus that this sublicensing ultimately secured AMD only around $200m (until the US entity list ban) out of the original $293m deal. At that time AMD was already making quick strides into the consumer market with its Ryzen 1000-series processors, which offered eight cores with modestly competitive performance while beating Intel on performance-per-dollar, giving AMD enough to reinvest in its key areas. The sublicensing ultimately provided AMD more of a safety net, depending on the success of the first generation Ryzen product portfolio.

AMD Does Due Diligence
Simply stating ‘AMD sublicensed the IP of one of its x86 designs’ sounds a bit farfetched on most days of the week. If either AMD or Intel believed that the opportunity to let others sell its CPU designs was profitable, how come it took until 2015/2016 to ever come to fruition? Part of this story covers that while there was clearly some money in it for AMD here, it didn’t fall foul of any Intel-AMD licensing agreements. And most importantly, it didn’t contravene any US laws regarding the export of high-performance computing intellectual property.

This last point is important. The US government gives every CPU that comes out of Intel, AMD, and others, a value based on its performance. This is some combination of FLOPs and power, and those that surpass a specific threshold are deemed too powerful to be sold in certain markets. This includes semi-custom processors, where AMD/Intel fiddle with the core count/frequency and provide off-roadmap parts.

AMD at the time made the following statement:

Starting in 2015, AMD diligently and proactively briefed the Department of Defense, the Department of Commerce and multiple other agencies within the U.S. Government before entering into the joint ventures. AMD received no objections whatsoever from any agency to the formation of the joint ventures or to the transfer of technology – technology which was of lower performance than other commercially available processors. In fact, prior to the formation of the joint ventures and the transfer of technology, the Department of Commerce notified AMD that the technology proposed was not restricted or otherwise prohibited from being transferred. Given this clear feedback, AMD moved ahead with the joint ventures.

AMD had contacted the DoD and DoC, as well as all others, and had been given the green light. The new microarchitecture was deemed of low enough performance to not hit any of the export bans. AMD was also given crystal clear confirmation that the ‘technology proposed was not restricted or otherwise prohibited from being transferred’, which is a rather stark statement. At this point it should be clear that AMD may have submitted a modified version of its IP to the relevant US departments, rather than the microarchitecture we saw in the Ryzen 1000-series. This is part of what this review is about.
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