Skipped display cycles on 120hz monitor

Hi Chris,

We just started using mworks with a new monitor, a display++ from Cambridge research systems. It’s a 120 hz monitor. Every second, I get tons of “skipped 1 display cycle” printed into the console. Do you know how I can fix this?

Thanks,

Simon

Hi Simon,

A couple questions:

  1. What model of Mac are you using?
  2. How many displays (internal and external) are connected to it?

120Hz is a pretty high refresh rate. It’s possible that your Mac’s GPU just can’t output frames at that rate reliably.

Alternatively, it may be able to drive a single, 120Hz display reliably but not a 120Hz display plus one or more additional displays. If you do have additional displays attached, I recommend disconnecting them and seeing how that affects MWorks’ display update performance.

Chris

We do have two displays connected to the computer, but the second one is
for the variables window/eye window, not a second display for the animal.
We’re running it on a 2017 Mac Pro (trash can), which I would expect could
do two monitors at a high refresh rate but maybe not? We don’t really need
the high refresh rate for what we’re doing right now but it is making the
console impossible to read because of the constant messages. Is there any
way to disable the skipped display cycle warning?

Simon

We do have two displays connected to the computer, but the second one is for the variables window/eye window, not a second display for the animal.

Regardless, the OS still has to deliver a new frame to it on every refresh, and the GPU has to split its time between the two displays.

We’re running it on a 2017 Mac Pro (trash can), which I would expect could do two monitors at a high refresh rate but maybe not?

You may have purchased it in 2017, but that model was released in 2013 and never updated. That said, I do all my development on a 2013 Mac Pro, and it seems to have no trouble driving two displays (one 4K, the other 1080p) at 60Hz.

Is there any way to disable the skipped display cycle warning?

Sure. Go to MWServer → Preferences → General and uncheck “Warn if stimulus presentation skips a display refresh cycle”.

Chris