4K monitor frame rates
does anyone know why a 4K monitor connected to a MacBook Pro 15" Late 2013 runs at 60 Hz if set to the standard scaling setting, and is limited to 24 Hz if set to the "More Space"/smaller text scaling setting? I ask because the resolution sent from the Mac to the EIZO is always 3840x2180, so there shouldn't be any difference in frame rate.
The connection is DisplayPort 1.2 MST. The display is an EIZO ColorEdge CG248-4K display. The monitor runs side by side with the internal MacBook Pro monitor. The MacBook Pro is running Yosemite 10.10.4.