Hi,
I am using Windows 7 and have 3x 1920x1080 monitors connected to a single graphics card (NVIDIA GeForce GTX 650 Ti Boost). Two monitors are connected via the card's DVI ports and one using HDMI.
Psychtoolbox recognizes the extended desktop as well as each screen separately. However, the size of the extended desktop screen - Screen('Rect',0) - only spans the first two monitors, regardless of the resolution used. Is there a way to get Psychtoolbox
to recognize the 3-monitor extended desktop?
-> No. The "screen 0 is first two monitors" is by design to cover dual-display stereo setups. It worked very well on Windows XP and earlier. Since the total redesign of multi-monitor support in Windows Vista and later, i think it won't work in a meaningful way without timing problems, visual stimulation/tearing artifacts on all but one displays, or various other bugs anyway, a design limitation of Windows Vista and later. That's why Windows is not recommended for multi-display vision science applications. AMD implemented a display driver hack they call "Single large surface" (SLS) mode in Eyefinity capable graphics cards with suitable displays, which works around Windows design flaws by tricking the OS into thinking multiple physical monitors are only one monitor (the single large display surface). This way one PTB "screen" would actually cover multiple physical displays and sometimes it works, sometimes not. Last tested around 2010 and got it working on one setup with 4 completely identical Displayport displays turning into an ultra-wide "monitor" under Windows-7. Maybe NVidia does something similar to outsmart Windows with their "Mosaic" or "Surround" technology for some graphics cards, but i never had access to such a card and suitable monitors, so this is not tested or supported in any way by me if you run into any kind of trouble. But if you'd try that let us know how well or bad it goes, so others can benefit. Matrox sells display extenders which allow to achieve the same effect in hardware, splitting up one video output into multiple monitors. That should always work, but is limited in what video resolutions and video refresh rates you can achieve by both the device and the resolution/bandwidth limits of a single output of the graphics card.
-> The other way to likely get this working is to upgrade to Linux.
The graphics card also has a DisplayPort connector - would that be better to pair with the DVI ports?
-> Doesn't matter for PTB or the other restrictions above. But in general it is a good idea to use the same type of connector for all displays that are supposed to show some coherent stimuli, as only then they can be driven by the same display pll and have a chance of getting synchronized in their display cycles. In your case single-link DVI should suffice for 1920x1080@60Hz, and HDMI acts as a single-link DVI port via passive adapter, so in that sense you'd probably be fine.
good luck,
-mario
Thank you in advance.
Cheers,
Benny
Benjamin Goller
Postdoctoral scholar
Dept. of Biological Sciences
Purdue University
Office: LILY G-305
Email: gollerb@...