In addition to the GPU usage in the task manage, you can also look at the logs for OpenALPR, there is indication in the logs if it is using the GPU or not.
Safe to assume this means the GPU isn't working?
ERROR loading detection library -- "alpredgegpu.dll": The specified module could not be found.
ERROR loading detection library -- "alpredgegpu.dll": The specified module could not be found.
ERROR loading detection library -- "alpredgegpu.dll": The specified module could not be found.
ERROR loading detection library -- "alpredgegpu.dll": The specified module could not be found.
ERROR loading library -- "alprocrgpu.dll": The specified module could not be found.
ERROR loading detection library -- "alpredgegpu.dll": The specified module could not be found.
ERROR loading detection library -- "alpredgegpu.dll": The specified module could not be found.
ERROR loading library -- "alprocrgpu.dll": The specified module could not be found.
ERROR loading detection library -- "alpredgegpu.dll": The specified module could not be found.
ERROR loading library -- "alprocrgpu.dll": The specified module could not be found.
ERROR loading detection library -- "alpredgegpu.dll": The specified module could not be found.
ERROR loading library -- "alprocrgpu.dll": The specified module could not be found.