AI Overview
Intel abandoned Fully Integrated Voltage Regulators (FIVR) due to efficiency issues, particularly with different processor workloads, and physical design constraints like heat and die area
. The FIVR technology, first used in the Haswell generation, proved to be inefficient for high-TDP processors during light workloads and low-TDP processors during heavy workloads. Consequently, the company removed it in favor of external motherboard-based voltage regulators, which offered a more adaptable and efficient power delivery solution for its Skylake processors and beyond.
Reasons for abandoning FIVR
- Energy inefficiency: FIVR was not consistently energy efficient across all types of workloads. For example, it was less efficient on high-TDP processors during computationally light tasks and could be a bottleneck for low-TDP processors attempting heavier workloads like Turbo Boost.
- Physical and thermal constraints: Integrating all voltage regulation components onto the CPU die was challenging for physical design. It created heat and took up valuable silicon real estate, which could be better used for other processor functions.
- Workload flexibility: The external Motherboard-Based Voltage Regulator (MBVR) approach allowed for greater design flexibility. By having the voltage regulators on the motherboard, Intel could design power delivery systems optimized for specific processors and motherboards, rather than a single integrated system that might not be ideal for every scenario.
Legacy and future
- Skylake's return to external VRMs: Intel dropped FIVR starting with the Skylake generation, moving back to a more traditional power delivery architecture where the voltage regulation modules were on the motherboard.
- FIVR's potential return in different forms: Although FIVR was dropped, Intel has explored related technologies. For instance, it experimented with Digital Linear Voltage Regulators (DLVR) for power saving, but this was also reportedly scrapped for Raptor Lake due to performance concerns. Intel's Core Ultra processors feature a different on-die voltage regulator technology called High-Speed On-Die Linear Voltage Regulator (DLVR) that is designed to be more efficient and responsive.
