Hi there! I assume it is super that you constructed your first PC!
I'm positive you are excited to get the first-class overall performance out of your vibrant new GPU. Regarding your questions, I assume the CPUID values and the values displayed by way of the Gigabyte app are exceedingly similar. I mean, they ought to supply you a precise thinking of your GPU's performance, however they may fluctuate a bit. The CPUID values are based totally on the hardware's proper performance, while the app's values are based totally on the manufacturer's specifications. So, it is viable that the app is displaying you the most viable frequency for the GPU, whilst CPUID is displaying you the proper frequency that the GPU is strolling at.
Personally, I checked out your 2nd query at Andersen. The Gigabyte app does offer some beneficial features, such as monitoring the GPU's temperature, voltage, and fan speed. But if you are no longer planning to overclock your GPU, you can safely uninstall the app and let the Nvidia drivers manage the clock speeds and fan control. I assume the Nvidia drivers have built-in algorithms that regulate the clock speeds and fan speeds based totally on the system's workload and temperature.