Physical Unclonable Functions (PUFs) can be used for security applications such as authentication, secure key generation and so on. Especially, SRAM-based PUFs are major candidates because of small area and reusability of IPs. In this paper, we compare three SRAM-based PUFs, power-on with and without divided-power control and Low/Low write schemes, from the viewpoints of uniqueness and reliability. By the measurement results of test chips fabricated in a 45-nm process technology, although uniqueness are almost the same in three schemes, we confirmed that power-on with divided power-control achieves higher reliability.