Trying to make sense of mobile SSD connectors

[Yuriman]

I'm trying to make sense of the following terms:

mSATA
mini PCIe
M.2

Take this ASRock board, for instance:

http://www.newegg.com/Product/Produc...82E16813157374

Newegg lists it as having two mini PCIe slots, one of which is populated with a WiFi module. However, the board's description claims that the second is an mSATA connector:

Onboard mSATA

The mSATA connector can be used to connect a Solid State Drive (SSD) for internal storage. With an SSD paired with an HDD, users are able to feel the speed of SSD Caching with Intel® Smart Response Technology.

So, which is it?

mSATA and mini PCIe seem to have the same socket, which is confusing, but a quick google suggests that they are distinct electrical designs and are not cross compatible. Do these two connectors not share compatible devices, despite having the same shape? Would the WiFi module work or not work in the second socket, called "mSATA" in the board's description? Would an "mPCIe" SSD like this work in the WiFi module's socket, but not work in an mSATA socket?

Looking at mydigitalssd.com, it appears they currently sell "mSATA" and "M.2" drives, but no mPCIe drives, which suggests to me that they might be on their way out, if they were ever a real thing and not just an artifact of changing terminology.

So, my guess is this:
-mPCIe SSDs are their own thing, and rare, but will work in the same slot as a mini PCIe WiFi module, and not in the mSATA slot which is superficially identical
-mSATA SSDs are very common, and share the same socket with mini PCIe WiFi modules, but they and their sockets are not electrically cross compatible
-M.2 isn't really a thing yet, at least in ITX desktops, but is showing up in a lot of laptops

So, what works in the second socket on the ASRock board, and what doesn't? How can I tell the two sockets apart?


Furthermore, what's the difference between mPCIe (SATA) and mPCIe (PATA)?
Source: http://www.newegg.com/Product/Produc...16%20600038517

????

 

[VirtualLarry]

mSATA and mini-PCIe are the same socket, physically, but mSATA generally has a longer length before the mounting screw. Generally, mPCI-E is half the length (used for wifi).

mSATA uses SATA electrically. mPCI-E is PCI-E. They are not electrically the same. The socket can be one or the other, or both, depending on how it is wired. Generally, the mobo manual tells you if the slot is for mSATA or mPCI-E or both.

 

[Yuriman]

Thanks Larry. So it's possible for the slot to be both? I'll suppose I'll need to try a WiFi card in my spare slot. The manual isn't clear for my Zotac board.

I'm in the early stages of planning an ITX gaming build for my sister, and the idea of getting rid of a few wires by going with an M.2 or mSATA SSD is appealing. I haven't been able to find any decent reviews on them though. Are they generally identical to their 2.5" counterparts, or will they perform differently? They're priced about the same.