So I was watching Digital Foundry’s coverage on Seagate’s proprietary SSD for the Xbox Series X, and it dawned on me the 3 slots to the NVMe’s pins are literally the same as the Sony XQD card and CFExpress.
If you look at their official video, there are 3 slots for where the pins are… guess what XQD and CFExpress have?
The “Proprietary” slot is just a CompactFlash association CFExpress/XQD card slot.
XQD was in really wide use on the Sony FS7 camera that you may have seen people carrying around:
The new Mirrorless Nikon cameras even have this slot:
It’s kind of ironic that Microsoft adopts something from the CF card association which was originally a Sony product.
There were rumors it would accept CFExpress cards, but they might use the same form factor, but completely different electrical signals. Official CFExpress specs max out at PCI-E 3.0 x4. However, don’t expect them to follow the standard. They will add a proprietary controller that will mean CFExpress cards won’t work.
Edit: Tweet from Seagate:
Unique design and software/firmware = Proprietary. Wouldn’t be surprised if the pinout is different. The form factor is standardized, but I highly doubt the electrical pinout specs are CFExpress.