AMD's Ryzen exceeds its '25x20' power efficiency challenge

Pushing ahead to 7nm while increasing core counts certainly helped AMD.

Credit: AMD

AMD said Thursday that the company has met and even exceeded the “25x20” goal that it set in 2014, in which it challenged itself to improve the energy efficiency of its processors by 25X by 2020.

AMD said the actual proportion was 31.7 times the energy efficiency of its 2014 processor, the AMD “Kaveri” FX-7600P, which was rated at 35 watts TDP. (Thermal design power, or TDP, typically refers to the “worst-case” scenario for thermal power.) AMD compared it to the Ryzen 7 4800H, a 45W part that can be configured down to 35W. 

Though AMD didn’t provide PCWorld the actual results, analyst Keven Krewell of TIRIAS Research, who consulted on the project, said the energy-efficiency number was derived by dividing the result of the Cinebench R15 multithreaded benchmark by actual consumed power. Those results, for the FX-7600P and the Ryzen 7 4800H, were then compared. AMD said its processors reduced their average compute time for a given task by 80 percent from 2014 to 2020, while also achieving an 84-percent reduction in energy use.

AMD could have shown an even better improvement if it had selected a 25W TDP processor, Krewell added. That would have included AMD’s “Kabini” APU, which would include the Athlon 5350. (AMD said in a press release that it also compared the FX-8800P, the FX-9830P, the Ryzen 7 2700U, the Ryzen 7 2800H, the Ryzen 7 3750H, and the Ryzen 7 4800H in its energy-efficiency calculations.) 

A number of factors contributed to AMD’s improvements, which began when the company’s mobile power efficiency was "not competitive," Krewell said. Six years ago, the FX-7600P boasted just four cores and four threads, on a 28nm process. AMD has since leapt two additional process nodes, to 7nm. The Ryzen 7 4800H is now an insanely high-performance member of the Ryzen Mobile 4000 family, and an 8-core/16-thread part.

A significant chunk of AMD’s power efficiency can probably be traced to AMD’s process shifts, but the performance side of the equation has been lifted by AMD’s rapid increase in core count, improved “chiplet” design, plus algorithms like Precision Boost 2 and Extended Frequency Range to keep its Ryzen processors in the upper echelons of its boost frequencies as often as possible. Overall, however, more of AMD’s 25x20 achievement was enabled by the power side of the equation, Krewell said.

“They’ve added a lot more fine-grained power management over the years,” Krewell said. “Overall, they’re just better engineered.”

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Mark Hachman

Mark Hachman

PC World (US online)
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