The Nvidia driver enables counters within the operating system.
The Windows Performance Monitor application can be used to collect this information. Run "perfmon"
Add Counter
You can also use nvidia-smi to grab the information:
C:\User>"c:\Program Files\NVIDIA Corporation\NVSMI\nvidia-smi.exe" --loop=1 --query-gpu=memory.used --format=csv
memory.used [MiB]
230 MiB
230 MiB
Another option is GPUZ:
https://www.techpowerup.com/gpuz/
Additional info can be found here:
https://github.com/JeremyMain/GPUProfiler/wiki