Hi marcusn,
The Radxa Penta SATA HAT can use 3.5-inch hard disks. And we have updated the power selection section of the usage document[1] to help users choose the right power supply mode.
I checked the specifications[2] for the WD84PURZ and I couldn’t find its peak current, so I wasn’t quite sure it would work with the Penta SATA HAT.
We generally recommend that users use a hard disk with a peak current of less than 1.8A, and a hard disk with a capacity of less than 12T on the market will generally have a peak current of less than 1.8A.
The average read/write power consumption of the WD84PURZ is relatively low, and I suspect its peak current will not be very high.
[1] https://docs.radxa.com/en/accessories/penta-sata-hat/penta-for-rpi5#power-supply-selection
[2] https://documents.westerndigital.com/content/dam/doc-library/en_us/assets/public/western-digital/product/internal-drives/wd-purple-hdd/product-brief-wd-purple-hdd.pdf