Server CPUs are high performance, high-core count processors for enterprise applications. Server CPUs have tremendously large and fast current transients and require significant bypassing, careful PDN design, and large voltage guardbanding.
High current levels lead to a tremendous number of SoC power balls and bumps with a complex package substrate design. Optimizing power/performance by splitting voltage rails for independent core voltage island control proves difficult, if not impossible, due to complex power plane routing and bypassing requirements.
There is a better way. Design Server CPUs with Your Inner Power: Empower RIVRTM integrated voltage regulators (IVR) eliminate poor power signal integrity, reduce the number of balls and bumps required and enable as many independent local voltage islands on-chip as desired with straight forward single power plane package routing.