Progress comes quickly in the microprocessor business, but even so, it’s rare to see a company upgrade its flagship’s performance by 50% in just six months. RISC-V vendor SiFive wants to establish its credentials as a viable Arm alternative, and not just on the basis of cost, but in performance and power efficiency. The CPU licensor is gaining ground on its British rival, but it still has a long way to go.
The new P650 core upgrades the P550 announced in July with an additional execution unit, larger caches, better branch prediction, a different load/store pipeline, hypervisor support, and a handful of other tweaks. Integer performance improves by 50%, according to the company’s simulations. Most of that gain is through more instructions per clock (IPC), with the remainder due to a 10% higher maximum clock frequency.