Using novel chip-based fast differential calorimetry (FDSC) we have been able to determine thermophysical properties at several 10<SUP>5</SUP> K/s heating and cooling rates. In this way we can measure complete time-temperature-transformation diagrams in the undercooled liquid range upon heating and cooling, even for moderate glass formers (see, e.g., <I>Appl. Phys. Lett.</I> <B>104</B> (2014) 251908), and determine the corresponding critical rates of glass formation. At such high rates we were also able to detect new phase transition paths, e.g. a solid-state phase transformation via melting for a Au-based glass, and describe the underlying thermodynamics (<I>Nature Comm.</I> <B>7:11113</B> (2016), doi:10.1038/ncomms11113). These phase transition paths are also seen in binary metallic glass-forming liquids where various metastable phases form as a function of the ultrafast heating and cooling rates. Thus as they appear to be a common feature of many metallic systems, they may need to be considered in future phase transition theories.