2.2.4 Motherboard Storage Connectors - Notes

Storage Interface Comparison

Interface	Use	Power	Max length	Notes
SATA	Internal HDDs, SSDs, optical drives, and tape drives	Separate SATA power or Molex connector	1 meter	Installed in a drive bay
M.2	Internal SSDs	Power supplied over the bus with no separate cable needed	N/A, card form factor	Lengths include 42, 60, 80, and 110 mm; check motherboard compatibility
eSATA	External drives	No power over the cable	2 meters	Better shielding than internal SATA
eSATAp	External drives	Yes, combines eSATA and USB in one port	2 meters	Also called eSATA/USB Combo

The port is oriented horizontally.
Insert the card at an angle, push it into place, and secure it with a screw.
Available lengths include 42 mm, 60 mm, 80 mm, and 110 mm, so check motherboard labels for compatibility.
No separate power cable is needed.

eSATA's main drawback is that it does not provide power over the cable.
That works fine for 3.5-inch drives with their own power source.
It is limiting for 2.5-inch portable drives that rely on bus power.
USB 3.x and Thunderbolt have largely replaced eSATA because they offer higher speeds, more versatility, and power delivery.