# dual display under OS X **URL:** https://psychtoolbox.discourse.group/t/dual-display-under-os-x/1537 **Category:** Uncategorized **Created:** [August 9, 2005, 9:30pm UTC](https://psychtoolbox.discourse.group/t/dual-display-under-os-x/1537 "2005-08-09T21:30:06Z") **Posts on this page:** 1 **Page:** 1
### Author: ![Allen\_Ingling](https://avatars.discourse-cdn.com/v4/letter/a/a183cd/32.png) [@Allen\_Ingling](https://psychtoolbox.discourse.group/u/Allen_Ingling) #### Post date: [August 9, 2005, 9:30pm UTC](https://psychtoolbox.discourse.group/t/dual-display-under-os-x/1537/1 "2005-08-09T21:30:06Z")
hello, I'm new to PTB, and I'd like to use it to drive two monitors synchronously, yet independently, with precise timing under OS X (i.e. both monitors will be presenting different stimuli). I've read through as much information as I could, but it's still unclear to me whether this is possible with a single graphics card with two outputs (I have a GeForce4MX on a G4 running OS X 10.3.9). Does anyone have any experience with this? A previous thread said that mirroring is absolutely necessary under OS X, but mirroring obviously doesn't allow independence of the monitors. I tried writing some sample code to test this, and it didn't work correctly, but it was probably something I'm doing wrong. If anyone who has experience with this could give me some advice, I'd greatly appreciate it. thank you very much, Luke -- Lucas L. Sjulson Cornell/Rockefeller/Sloan-Kettering MD/PhD Program Laboratory of Neural Systems (Miesenboeck Lab) Yale University School of Medicine 295 Congress Avenue, Rm # 247 New Haven, CT 06519-1418 (203) 785-2311