Originally Posted by NintendoManiac64
You can always bring that down to 8ms of precision by running at 120Hz 1080p instead.
The program I linked uses the same line of thinking, but instead it increases the precision up to +- 1ms (1000hz) WHILE your monitor is only operating at 60hz using a few clever tricks.
Your whole screen updates every 16.66ms at 60hz, but what you gotta understand that the screen is actually updated line by line.
The display actually:
Reads line 1
Draws line 1
Reads line 2
Draws line 2
Phsyical time elapses between the monitors read operations.
If you unlock your graphics cards frame limiter, you can have have the entire frame data the monitor reads from between its line draw operations actually change at rates of 1000-2000+hz !!
If you do the math, with 1080 vertical lines, every time the monitor draws 65 lines, 1ms in realtime has elapsed.
This means if you are on drawing line 195, lines 0-65 are from 3ms old, lines 65-130 are 2ms old, lines 130-195 are 1ms old, line 195 is present time.
What you are left comparing between two displays are the most recently updated groups of lines but these lines are able to be present different at vertical locations between the monitors, both with accurate times. This will eliminate the effects of timing differences making the comparisons show 1ms of error. This is a significant increase compared to the frame method that will always have up to 16ms error due to signal timing differences.
With this trick, even tho the two monitors may have their draw operations out of sync, they will still display the most recently frame generated available by the graphics card when comparing groups of vertical lines. The graphics card is capable of 1000hz precision.
The SMTT v2 timer is the only way to measure lag with 1ms accuracy using a camera.
Browser based timers have will led to a +- 16ms accuracy, no matter your camera shutter speed!
A 16ms accuracy is worthless when comparing differences at these levels!
To use the program, simply compare the two most recent times displayed between the two cloned monitors. (Really thats it !!)