Air cooling still has a role in lower-density rooms and support spaces, but for GB200, GB300, and Vera Rubin-class systems, the thermal center of gravity has moved to liquid transport. The question is no longer which method is simpler; it is which method can sustain the load with the least waste and the most control.
- Air remains useful where density is modest and serviceability matters most.
- Water is the practical default for rack-scale AI heat rejection.
- Hybrid designs are often the best fit for mixed facilities.
For operators, the key is to align the thermal path with the workload, then maintain the controls, pumps, and water-side equipment with enough discipline that the plant does not drift under changing demand.
Sources: GB200 NVL72 · GB300 NVL72 · Vera Rubin · ASHRAE AI Data Center Energy Performance Framework · DOE cooling control systems
Data Center Health 