$ sudo dmidecode --type 9
# dmidecode 2.11
SMBIOS 2.6 present.

Handle 0x0023, DMI type 9, 17 bytes
System Slot Information
	Designation: Slot1
	Type: x16 PCI Express 2
	Current Usage: In Use
	Length: Long
	ID: 1
	Characteristics:
		3.3 V is provided
		PME signal is supported
	Bus Address: 0000:00:01.0

Handle 0x0024, DMI type 9, 17 bytes
System Slot Information
	Designation: Slot2
	Type: x4 PCI Express 2 x16
	Current Usage: Available
	Length: Short
	ID: 2
	Characteristics:
		3.3 V is provided
		PME signal is supported
	Bus Address: 0000:00:1c.2

Handle 0x0025, DMI type 9, 17 bytes
System Slot Information
	Designation: Slot3
	Type: 32-bit PCI
	Current Usage: Available
	Length: Long
	ID: 3
	Characteristics:
		5.0 V is provided
		3.3 V is provided
		PME signal is supported
	Bus Address: 0000:00:1e.0

Handle 0x0026, DMI type 9, 17 bytes
System Slot Information
	Designation: Slot4
	Type: x1 PCI Express 2
	Current Usage: Available
	Length: Long
	ID: 4
	Characteristics:
		3.3 V is provided
		PME signal is supported
	Bus Address: 0000:00:1c.0