IT takes effort to find the real or all differences...
Pure shall we say electrical specs or I/O specs are not the only differences.
The Gaming 5 has this "over" the Gaming 3.
Gold plated display and audio ports
High end Nichicon audio capacitors
PLUS What is in the BOX > Gaming 5 has 4 Sata Cables over Gaming 3 only 1 Sata Cable.
The Gaming 7 has this "over" the Gaming 5.
Marvell® 88SE9172 chip:
2 x SATA 6Gb/s connectors (GSATA3 6~7)
Support for RAID 0 and RAID 1
1 x Trusted Platform Module (TPM) header
1 x power button
1 x reset button
1 x Clear CMOS button
2 x BIOS switches
Voltage measurement points
PLUS What is in the BOX > Gaming 7 has 2 Sata Cables over Gaming 3 only 1 Sata Cable.