Which viewer do you mean? There are 3 popular ones:
All of them are confused by NVIDIA Optimus technology.
Therefore create an app profile in NVIDIA control panel.
Select NVIDIA in app profile, run viewer and save results.
Then select INTEL in app profile, run viewer again and save results again.
Otherwise GPU-Z Video card GPU Information Utility can hot switch GPUs.
This message was posted on behalf of Intel Corporation
Great suggestions from Stefan3D.
See the following link for Intel® HD graphics 530 specifications
Supported APIs and Features for Intel® Graphics Drivers