ALL 24.
I have the same board and PSU.
20 + 4 pin on my Maximus VII Hero
1 x USB 3.0 connector(s) support(s) additional 2 USB 3.0 port(s)
3 x USB 2.0 connector(s) support(s) additional 5 USB 2.0 port(s)
1 x M.2 Socket 3 for M Key, type 2260/2280 devices
1 x TPM header
8 x SATA 6Gb/s connector(s)
1 x CPU Fan connector(s) (1 x 4 -pin)
1 x CPU OPT Fan connector(s) (1 x 4 -pin)
4 x Chassis Fan connector(s) (4 x 4 -pin)
1 x 24-pin EATX Power connector(s)
1 x 8-pin ATX 12V Power connector(s)
1 x Front panel audio connector(s) (AAFP)
1 x System panel(s) (Q-Connector)
1 x MemOK! button(s)
1 x Thermal sensor connector(s)
1 x Power-on button(s)
1 x Reset button(s)
1 x Clear CMOS button(s)
1 x ROG extension (ROG_EXT) header(s)
1 x KeyBot Button
1 x Sonic SoundStage Button