Combine Two SSD to 1 Volume?

Here’s what I found on OWC web site: OWC Aura Pro X2 2 TB Blade SSD (NVMe/PCIe 3.1 x4)

Here’s a good reference on the Apple SSD’s The Ultimate Guide to Apple’s Proprietary SSDs So you have a reference on what’s needed for your system.

As far as combining the two dissimilar SSD drives SATA III (6.0 Gb/s) & PCIe/NVMe into either a JBOD into a linear single drive or RAID just won’t work as the I/O speeds are just to different. You also run the risk of trying to recover your data if your system dies will be more complex. Setting up a Fusion Drive using two SSD’s also makes little sense as well as it would be wasteful.

Most pro’s using iMac’s go with a dual drive setup. Using the blade SSD as their boot drive with their apps and depending on what they are doing leaving at least 1/3 (256/512 GB) to 1/4 (1 TB or larger) of the drive free for V-RAM, caching and paging within the apps. Video editors might go with even larger SSD’s so they can push the free space as their apps can leverage this space as scratch space.

So the bottom line here is stick with two independent discreet drives for the best config here!