The standard cooling approach for medium to high power microprocessor devices remains air cooling. However, increasing power density has driven overall interest in alternative, more efficient methods of cooling microprocessors. In this work we present and compare performance results for three different cooling approaches: Air cooling, single-phase liquid cooling and chip-embedded two-phase liquid cooling each applied to the exact same processor devices. The devices were operated over a wide range of frequencies and workload, creating a range of operating powers that varied with the utilized cooling technology. The single-and two-phase liquid cooling approaches provide substantial reductions in system power usage and operating temperatures, with both approaches well-suited to chiller-less facility level implementation. The two-phase cooling approach has the advantage of extendibility to 3D stack cooling at the same level of cooling effectiveness. Overall, the improved thermal performance and efficiency of the described alternatives to air cooling make them prime candidates for implementation in future systems.