So I am looking at upgrading to SSD drives in about a half dozen Lenovo ThinkCentre M93z All-in-One PCs. I can either get 2.5" drives and use a bracket, or use the mSATA connector on the motherboard. But which is faster? mSATA is typically based on the PCI Express 1x standard. The speeds for each are as follows:
PCIe v1 1x = 2.5Gbps
PCIe v2 1x = 5.0Gbps
PCIe v3 1x = 8.0Gbps
SATA 1 = 1.5Gbps
SATA 2 = 3.0Gbps
SATA 3 = 6.0Gbps
Now the question is if the mSATA slot conforms to PCIe v1, 2, or 3. If it is v3 it will be faster. The chipset on the M93z is the Intel 8 Series/C220. Intel's technical documents show that the SATA controller is capable of SATA 3 6.0Gbps speeds, while the PCI Express implementation is v2.
So this indicates that an SSD mounted on the mSATA slot would max out at 5Gbps, while the SATA connection would allow 6Gbps, making it faster.
The problem with going to SATA route is the way the hard drive is installed. Although many of the other components in this system are laptop form-factor like the RAM and optical drive, a full 3.5" desktop hard drive is being used. There are no SATA cables with the drive mating right up to the connectors. So I can either use a standard 2.5" to 3.5" bracket and find really short cables that may not make the clearance, or I can buy a bracket that features integrated SATA connectors that route down to the spot where they normally would on a 3.5" drive. Fortunately, these exist!
Lenovo just had to make it hard. But of course they probably don't care too much about making it easy to upgrade.