HiFrom what I can see all the fans apart from SYS_FAN1 are PWM. SYS_FAN1 is just standard 3 pin. You can see the pin outs on page 22 here:http://download.gigabyte.eu/FileList/Manual/mb-manual_ga-z77(h77)-d3h(-mvp)_v1.1_e.pdf
Yes they all physicaly have four pins but that doesn't mean that they are all electrically connected.