A white paper from AMD, presented at the International Solid State Circuits Conference (ISSCC), contained details about the Zen x86 core and the design techniques behind it. Two impressive facts came to light during the session attended by engineers from various chip making firms. Firstly, AMD’s 14nm Zen x86 cores fit into a 10 per cent smaller die than Intel’s second generation 14nm processor cores. Secondly AMD’s chip construction techniques enabled a reduction in switching capacitance by 15 per cent compared to its existing chips.
A report from the ISSCC by the EETimes says that “analysts and even Intel engineers in the session said the Zen core is clearly competitive.” Whether AMD can save money on manufacturing, thanks to its more compact die requirements, remains to be seen and can be impacted by many further variables.
Looking at the table above you can see that the 14nm Zen x86 quad-core cluster takes up 44mm2, compared to an Intel Skylake quad-core at 49mm2. AMD has previously worked very hard and enjoyed excellent results from design-level enhancements. For example it managed to implement a 30 per cent reduction in layout area by using a high density cell library template for the Steamroller chip design, resulting in both area and power reductions.
Switching capacitance with Zen has been reduced by 15 per cent. The white paper notes that AMD moved to metal-insulator-metal capacitors in its latest designs which has “helped lower operating voltages and provide greater per-core voltage and frequency control”. The EETimes reports that AMD engineers worked for over a year on reducing switching capacitance.