๐ค AI Summary
This study addresses the inefficiency of conventional data center cooling paradigms, which adhere to a โcolder is betterโ principle despite modern low-voltage Intel Xeon CPUs exhibiting inverse temperature dependence (ITD)โa phenomenon where lower temperatures degrade energy efficiency. For the first time, this work empirically validates ITD on commercially available CPUs, identifies the temperature point that maximizes energy efficiency for each CPU model, and proposes a dynamic inlet temperature control strategy based on CPU thermal grouping. By challenging the traditional cooling assumption, the proposed approach achieves a 4%โ13% reduction in total energy consumption in real-world cloud data centers without compromising performance or system reliability.
๐ Abstract
As data center energy demand approaches grid-level constraints, optimizing conventional server infrastructure is essential for sustainable growth. The long-standing assumption that "cooler is better", i.e., lower CPU temperatures reduce power, does not fully hold for modern low-voltage CPUs, where inverse temperature dependence (ITD) drives higher supply voltages at lower temperatures. This creates a non-monotonic performance-per-watt curve where efficiency peaks at an intermediate thermal point. In this paper, for the first time, we empirically characterize ITD on production Intel Xeon CPUs and demonstrate that efficiency-optimal temperatures are CPU part-specific, and frequently higher than typical data center operating conditions. Measurements from commercial cloud data center platforms (Amazon, Equinix) reveal that approximately half of modern high-power CPUs operate about 10ยฐC below their efficiency-optimal thermal point. By implementing ITD-aware thermal grouping of CPUs and inlet temperature adjustments, data center operators can optimize facility-level cooling and overall sustainability. Our case study shows that this approach can reduce total data center energy by 4-13% without sacrificing performance or reliability.