I have a LCD and CRT connected to a winXP machine, and want to run the CRT at a much higher resolution than the LCD. I know this isn't recommended for timing, but for this experiment that doesn't matter.
BUG(?): If I run gratingdemo with the output monitor set to number 1 (the CRT, running at 1600x1200) about a quarter of the display intrudes into the LCD (screen 2, 1280x1024). If I do the same with the much more modern ImagingStereoDemo(4) it fails the same way.
full status:
>> ImagingStereoDemo(4)
PTB-WARNING: Startup test of beamposition queries for high precision timestamping detected problems on your graphics card + driver combo.
PTB-INFO: Seems beamposition queries are unsupported whenever the display is in a vertical retrace state.
PTB-INFO: I will enable a work-around which should satisfy the timing needs of most applications, ie.
PTB-INFO: robust and jitter-free deterministic timestamps. However, all reported timestamps may have a
PTB-INFO: constant offset of up to the duration of the vertical blanking interval (max 1 msec worst case)
PTB-INFO: of your display. Read 'help BeampositionQueries' on how you can remove that bias by some manual
PTB-INFO: intervention, should you need that last bit of accuracy. A second drawback is increased cpu load,
PTB-INFO: which may cause louder air-fan noise due to heat production and lower battery runtime of laptops.
PTB-INFO: This is Psychtoolbox-3 for Microsoft Windows, under Matlab 32-Bit (Version 3.0.11 - Build date: Sep 11 2013).
PTB-INFO: Type 'PsychtoolboxVersion' for more detailed version information.
PTB-INFO: Most parts of the Psychtoolbox distribution are licensed to you under terms of the MIT License, with
PTB-INFO: some restrictions. See file 'License.txt' in the Psychtoolbox root folder for the exact licensing conditions.
PTB-INFO: The detected endline of the vertical blank interval is equal or lower than the startline. This indicates
PTB-INFO: that i couldn't detect the duration of the vertical blank interval and won't be able to correct timestamps
PTB-INFO: for it. This will introduce a very small and constant offset (typically << 1 msec). Read 'help BeampositionQueries'
PTB-INFO: for how to correct this, should you really require that last few microseconds of precision.
PTB-INFO: Btw. this can also mean that your systems beamposition queries are slightly broken. It may help timing precision to
PTB-INFO: enable the beamposition workaround, as explained in 'help ConserveVRAM', section 'kPsychUseBeampositionQueryWorkaround'.
PTB-INFO: OpenGL-Renderer is NVIDIA Corporation :: GeForce GT 545/PCI/SSE2 :: 4.2.0
PTB-INFO: VBL startline = 1200 , VBL Endline = 1200
PTB-INFO: Measured monitor refresh interval from beamposition = 16.667071 ms [59.998545 Hz].
PTB-INFO: Will use beamposition query for accurate Flip time stamping.
PTB-INFO: Measured monitor refresh interval from VBLsync = 16.666923 ms [59.999078 Hz]. (50 valid samples taken, stddev=0.031694 ms.)
PTB-INFO: Reported monitor refresh interval from operating system = 16.666667 ms [60.000000 Hz].
PTB-INFO: Small deviations between reported values are normal and no reason to worry.
PTB-INFO: Stereo for free fusion or dual-display desktop spanning enabled (2-in-1 stereo).
PTB-INFO: Psychtoolbox imaging pipeline starting up for window with requested imagingmode 1027 ...
PTB-INFO: Will use 8 bits per color component framebuffer for stimulus drawing.
PTB-INFO: Will use 8 bits per color component framebuffer for stimulus post-processing (if any).