Both versions of the Intel® SSD 750 Series are PCIe* Gen3 x4 devices with NVMe interface. The performance specs are the same for both models. The advertised performance is stated in page 8 if the Intel® SSD 750 Series Product Specification.
The motherboard you are considering should be able to handle either version of the drive.
Here is a quick description of the 2 form factors, please check the Product Specification document linked above for details:
- The Add-in card is Half-height Half-length and requires a single slot x4 connector, you could use the x16 slots for other devices.
- The 2.5-inch form factor requires the computer to have a U.2 compatible connector like the ASUS Hyperkit* (allowing the PCIe* Gen 3 x4 connection with a M.2 adapter, and SFF-8639 to Mini-SAS HD connector cable)
Thank you Jonathan - that was exactly what I needed.