Hi I’m working on a windows 10 with a GeForce GTX 650. For the experiment I’m running accurate timing is essential. Basically I’ve just been having issues with the VBL sync function and I’m looking for a work around. I’ve read all of the ‘help BeampositionQueries’ and ‘help synctroubles’ and made all necessary adjustments on the nvidia control panel yet still I’m met with a “very small and constant offset”.
I’ve ran a few test such as the ‘PerceptualVBLsync test’ and the ‘BeampositionTest’ but the results just confirmed that there was a small issue that resulted in a very small but constant offset. Does anyone know how to find out what exactly the offset within the system is so that I can account for it better? any help is greatly appreciated thank you.
Sorry but for accurate timing, Windows 10 is not recommended. Dual-boot Linux and use an AMD GPU to optimise your experimental setup for precise timing…
In principle Ian is right. But the output you posted looks not too bad, assuming this is a single display setup on a standard DPI monitor. Obviously beamposition timestamping should be used, not sure why you intentionally disabled it - that is certainly bad for timing.
The “very small constant offset…” info is common on Windows, especially with NVidia graphics. How to prevent it is told in the info message. But the small constant offset is at most one VBLANK duration, typically less than 5% of a video refresh duration on a standard display, iow. probably less than 0.8 msecs in this specific case. So you should be fine for most paradigms. If you really need better than that precision, switching to Linux is certainly a more sane choice. A NVidia gpu as old as a Kepler class GTX 650 might even be fine performance-wise on the nouveau Linux open source driver for good/reliable timing and timestamping.
