How to set it up:
- A small script on each terminal records each tick's time and bid/ask.
- Count ticks per minute and compare by hour, especially 08:00 to 08:30 London.
- Check how often both feeds show the same price at the same second.
Useful follow-up: compare the M1 high and low on both feeds for the London open. If one feed regularly shows extremes the other doesn't, stops near those extremes behave differently.
This also explains why two traders on different brokers see slightly different charts.
Has anyone compared feeds for the same broker on demo versus live?