Thank you for contacting the Intel Community Support.
We can provide you with the Intel® VROC Supported Configurations depending on your version, but checking with ASUS would be the best option in order for you to get information or details specific for your system because, as mentioned in that article, if any of this information conflicts with the support information provided by a platform OEM or ODM, the platform documentation and configurations should take precedence.
Personally. I have tested an ASUS Hyper M.2 card (validated by ASUS) using VROC with four 512GB drives without issues, and I'm not aware of a capacity limitation, but again, the best option would be to check with the manufacturer of the system as they can provide you more accurate information (since this hyper M.2 card, for example, is not an actual configuration or setup validated by us).
If you have any questions and I can be of assistance, please let me know.
Intel Customer Support Technician
A Contingent Worker at Intel