A GPU (Graphic Processing Unit) spectrometer for the ALMA (Atacama Large Millimeter/submillimeter Array) Total Power Array has been developed by the KASI and the NAOJ (National Astronomy Observatory of Japan). It is a first in-kind contribution of the KASI to the ALMA international collaboration. The development project went through a series of milestones, from a concept design review in 2016 to commission and science verification in 2023. During the ALMA maintenance period of February 2022, the GPU spectrometer was installed in a technical building at the Array Operation Site by its developers from the KASI and the NAOJ. Right after the installation, SiO (J=2-1; v=1) 86 GHz maser spectral lines toward the Orion KL region were successfully detected using the spectrometer. The spectrometer will be used from the ALMA Cycle 10 (October 2023) for science observations.