The core was developed by Micro Magic Inc. (Sunnyvale, Calif.), a long-standing processor design services firm and EDA tools developer. The company had already claimed that its design was the fastest 64-bit RISC-V processor (see EDA company claims world's fastest 64bit RISC-V core and RISC-V core out-clocks Apple, SiFive; available as IP).
But in an interview with eeNews Europe Mark Santoro, CEO of Micro Magic, said the processor core had also been designed so that it can operate down to at least 350mV, near the threshold voltage of the manufacturing process. (see CEO interview: Silicon Valley is still the place where the magic happens). This allows a sacrifice in performance to achieve considerable power savings.
At 1.1V the RISC-V core operates at a clock frequency of 5.1GHz and consumes about 500mW. At 350mV the core can still be operated at a clock frequency of 1GHz and consumes just 10mW.
Micro Magic has chosen the CoreMarks benchmark from Embedded Microprocessor Benchmark Consortium (EEMBC) as a measure of performance. At 5.1GHz the processor achieves 13,333 CoreMarks and at 1GHz it achieves 2,500 CoreMarks.This gives CoreMarks per watt figures of merit of 26.6k CoreMarks/W at 5.1GHz and 250k CoreMarks/W at 1GHz. This means by reducing the voltage to a third and the clock frequency by a factor of five a power efficiency increase of more than 9 can achieved.
Micro Magic has made these measurements on real silicon manufactured using a multiproject wafer run. And no "binning" of chips was used in the benchmarking so the same chip can achieve both 5.1GHz (500mW) at 1.1V and 1GHz (10mW) at 350mV. This opens up the prospect of dynamic performance-power scaling.
Next: What foundry? what process?