One possible reason for the discrepancy may be that one of the browser is active and the other not. I suppose the active one may be faster.
Other reason may be that the Generator finds different strategies, pushes to Collection and draw chart. This all may take different time.
I wrote a simple speed test that calculates one strategy 1000 times and shows the time in milliseconds.
In order to do the test follow the steps:
1. Open the core app here: https://eas.forexsb.com/
2. load MetaTrader Demo Data H1 in Editor.
3. Open the Developer Console (F12)
4. Paste the following function:
function speedTest(cycles) {
console.log("Test started. Please wait...");
const strategy = eas.strategy;
const settings = eas.settings;
const dataSet = eas.dataManager.dataHolder["MetaTrader-Demo EURUSD H1"];
const startTime = Date.now();
for(let i = 0; i < cycles; i++) {
strategy.setAllIndicatorsDirty();
BacktesterHelper.calculateStrategy(strategy, dataSet);
Backtester.calculate(strategy, dataSet, settings);
}
const time = Date.now() - startTime;
console.log(cycles + " cycles calculated for: " + time + "ms");
}
5. Run the test with this call: speedTest(1000);
It shows 10250 - 10750 ms on my machine on Chrome. Lower is better.
Edit: The result greatly depends on what strategy you have in the Editor. You may test with more complex or more simple.