What is hardsync?
Hardsync means that that display update timing (when fipping/swapping back and front buffers) are handled by the hardware (graphics card) driver. On some systems however (because drivers are kernel programs) this is a BUSY wait, that is the CPU cannot do anything else in the mean time. what is softsync?
SoftSync means that display flipping is controlled by a software timer. This means that the program instead IDLE waits (that is, the CPU can execute other programs until the timer fires). Unfortunately it means that the display "swap" doesn't take place on the electon beams vertical sync trigger (when the electron beam moves from the bottom of the display to the top of the display), but instead you can use it (not recomended tho') as a mostly reliable game timer, without adding additional logic. is the monitor refresh rate actually ever changed?
Yes. A hardsync will (should ?) change the refreshrate (it does here). What happens if I specify -1|HARDSYNC? will this change the monitor's refresh rate from 60hz?
No. Mine is in 75Hz (the default) vertical refresh rate.