How long it takes depends on the power of the GPU and the number of megapixels (not megabytes) per image. (Megabytes don't help for comparison because 45MB can represent a variety of image sizes, because of variables such as compression type used, if any, and bit depth.)
There have been some tests around the web where multiple people have downloaded the same 60MP sample raw file and run Denoise on the systems they own. In general, what was found is:
Older/weaker GPUs can take 5 to 45 minutes per image.
Recent low/midrange GPUs can take 1 to 3 minutes per image.
The fastest current GPUs in PCs and Macs can take under 10-15 seconds per image.
The speed for your images depends on how many megapixels your raw files are compared to 60MP. For example, if your files are 20MP (which is 1/3 of 60), then you can assume Denoise times for your 20MP images would be about 1/3 of the time estimates above.
For Windows PCs, those who need maximum Denoise performance have been using the upper end Nvidia discrete GPUs, like the 30x0/40x0/50x0 series.
For Denoise, CPU performance and RAM amount don’t make much difference. Only the GPU does.