Chip cooling at 1000W and beyond

Key takeaways:

• Iceotope’s single‑phase Precision Liquid Cooling© has demonstrated stable chip cooling at 1000 W, breaking the perceived ~400 W limit for single‑phase systems and matching or exceeding two‑phase immersion performance.
• The tested KUL SINK heat sink achieved low, power‑agnostic thermal resistance (0.039 K/W at 1000 W and 7.01 l/min), with results indicating scalability to at least 1.5 kW chips.
• Precision Liquid Cooling supports future high‑TDP CPU/GPU roadmaps while enabling up to 40% lower energy use, up to 100% water savings, and 6x rack density uplift versus air and tank immersion approaches.

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This whitepaper documents how Iceotope’s single‑phase Precision Liquid Cooling achieves reliable chip‑level cooling at 1000 W and is positioned to support even higher power densities demanded by AI and next‑generation CPUs and GPUs. Historically, single‑phase liquid cooling was perceived as limited to around 400 W, but rising TDPs and sustainability requirements are forcing the industry to adopt solutions that can scale well beyond this level.

Iceotope evaluated four KUL SINK heat sinks using Intel’s Airport Cove thermal test vehicle, a thermal emulator for 4th Gen Intel Xeon Scalable processors. The copper KUL SINK was supplied with Shell S3X dielectric coolant at 40 °C over flow rates up to 7.5 l/min, while the TTV was driven up to 1000 W with uniform die heating. Detailed instrumentation, including embedded thermocouples, enabled calculation of thermal resistance from fluid to Tcase and assessment of TIM behavior.

At 7.01 l/min, the copper-pinned KUL SINK reached a thermal resistance of 0.039 K/W at 1000 W, an 11.4% improvement over a like‑for‑like tank immersion product with a forced‑flow heatsink. Thermal resistance remained essentially constant as power increased from 250 W to 1000 W, giving high confidence the design will behave similarly at 1.5 kW and beyond.

Looking forward, the paper argues that Precision Liquid Cooling, using minimal, safe single‑phase dielectric fluids, can meet future processor roadmaps while reducing energy use by up to 40%, eliminating water consumption, and enabling 6x density uplift in familiar rack‑based form factors.