The hidden limits of chart history in MT4
Posted: Sat Oct 31, 2026 8:43 pm
MT4 stores a fixed number of bars per chart, and the default setting is much lower than people assume. When a chart is set to unlimited bars or a huge number, the platform slows down, and tick processing falls behind.
That slowdown is subtle. The chart still updates, but with a lag of a fraction of a second during busy moments, enough to affect a scalper who reacts to what is on screen.
The same applies to history loaded for expert advisors. A strategy that scans fifty thousand bars on every tick will cause delays, especially on weaker hardware.
A sensible approach is limiting history to what the strategy actually needs. If the logic uses the last 200 bars, loading a hundred thousand does nothing except slow things down.
Another habit worth adopting is restarting the platform at the start of each trading day, which clears memory and rebuilds the tick buffer.
How many bars are loaded per chart, and has trimming the history changed the way the platform feels during busy periods?
That slowdown is subtle. The chart still updates, but with a lag of a fraction of a second during busy moments, enough to affect a scalper who reacts to what is on screen.
The same applies to history loaded for expert advisors. A strategy that scans fifty thousand bars on every tick will cause delays, especially on weaker hardware.
A sensible approach is limiting history to what the strategy actually needs. If the logic uses the last 200 bars, loading a hundred thousand does nothing except slow things down.
Another habit worth adopting is restarting the platform at the start of each trading day, which clears memory and rebuilds the tick buffer.
How many bars are loaded per chart, and has trimming the history changed the way the platform feels during busy periods?