Finally reporting back with my findings. I ran some benchmarks using Sandisk 6Gbps 2.5 SSD drives attached. Assumption is that the SSDs are more than enough to saturate the bandwidth. Chino de Oro was correct with his response. Despite what it stated in the documentation for the XPS 8950, the SATA3 port runs at SATA III speeds. I used the Dell SATA cables, initially to see if the cables were limited in some manner, but the cables ran at SATA III speeds. SATA0
Since the 8950 has four SATA ports, I wanted to confirm that SATA 3 can be used for a 4th storage drive. The specs list the internal SATA ports as:● Three SATA 3.0 slots for 3.5-inch hard drives● One SATA 3.0 slot for optical drive or 3.5-inch hard drive I would like to know if the SATA 3 port, that is currently being used for the ODD, would limit the performance with an SSD.I find it weird that it's listed as specifically for an ODD, as opposed to just stating that all four SATA ports are equal.e.g.  I can connect an SSD, but it is limited to SATA 1 speeds of 1.5Gb/s There is no extra description with regards to the SATA ports, other than what I shared above. Thank you.
XPS 8950, using SATA 3 port for SSD/HDD four drives