MT5 Backtest Tick Data Quality — OHLC, 1-Minute OHLC, and Real Ticks Explained

When running a backtest in MT5's Strategy Tester, you will notice a setting called "Model." The model you choose has a significant impact on the accuracy of your results. For scalping EAs in particular, picking the wrong model leads to the classic problem of "looks great in backtests, fails completely in live trading."

The Three Backtest Models

MT5 Strategy Tester offers three models to choose from.

1. Every Tick (Real Tick Data)

This is the most accurate model. It replays every single quote change that occurred in the real market.

• Spread fluctuations are fully reproduced
• Provides high-fidelity simulation including order-book dynamics
• Slowest processing time (H1 over 10 years can take 30 minutes to over an hour)
• Requires large data files

Recommended for: Scalping strategies (M15 and below), strategies where spread impact is material

2. 1-Minute OHLC (Ticks Generated from 1-Minute Bars)

Simulates tick movement from the four price points (Open, High, Low, Close) of each 1-minute bar.

• Less accurate than real ticks, but sufficient for swing strategies
• Well-balanced processing speed (H1 over 10 years typically takes 5–15 minutes)
• Closest to the approach familiar to MT4 users

Recommended for: H1 and H4 swing EAs, cases where moderate accuracy is acceptable

3. OHLC Only (Bar Close Prices)

Validates using only the four price points of each bar (Open, High, Low, Close).

• Fastest processing (completes in a few minutes)
• Lowest accuracy of the three models
• Produces particularly large errors for strategies using ATR-based SL/TP

Recommended for: Quick sanity checks only — not suitable for serious validation

Why Scalping EAs Require Real Ticks

Backtesting a scalping EA (M15 or below) with the 1-Minute OHLC model introduces the following problems.

Problem 1: SL and TP Hit Order Becomes Ambiguous

In the real market, it matters whether the high or low of a bar was reached first. With 1-Minute OHLC, the sequence of High and Low within a single minute is unknown, so the model cannot accurately determine "did the SL get hit first, or did the TP?"

Example: Price movement within one minute
  Reality:  High reached first → then price falls (TP triggered before SL)
  OHLC model: High=TP level, Low=SL level — the order is unknown

Because scalping trades have SL and TP placed close together, this ambiguity has a large impact on simulated performance.

Problem 2: Spread Spikes Are Not Reproduced

The 1-Minute OHLC model does not replicate the sudden spread widening that occurs around major news releases. Since scalping strategies are the most sensitive to spread, backtests run with a fixed spread will produce overly optimistic results.

How to Download the Data You Need for Backtesting

Before MT5 can run a backtest, the historical data must be downloaded to your terminal.

Step 1: Download Historical Data

1. Launch MT5 and log in to your broker account
2. Go to Menu → Tools → History Center (or press Ctrl+H)
3. Select the target symbol (e.g., XAUUSD)
4. Right-click the desired timeframe (M1 is the most important) and choose "Download"
5. Wait for the download to complete (this can take anywhere from a few minutes to tens of minutes on the first run)

Step 2: Check Data Quality

Once Strategy Tester is open, the "Quality" column shows the quality level of your data.

Quality 99%  → Real tick data — high-accuracy backtesting is possible
Quality 90%  → Pseudo-ticks generated from 1-minute bars
Quality 25% or below → OHLC only (low accuracy)

Always confirm you have 90% quality or higher — ideally 99% — before running your backtest.

Recommended Backtest Settings for EAs on This Site

Estimated Backtest Processing Times

Environment: Core i5 equivalent, 8 GB RAM, SSD, XAUUSD over 10 years

When running MT5 backtests on a VPS, performance depends on CPU capability. CPU usage will approach 100% during processing, so running backtests while an EA is actively trading can affect live performance.

Summary

• Swing strategies (H1 and above): 1-Minute OHLC is sufficient (good balance of speed and accuracy)
• Scalping strategies (M15 and below): Use Every Tick (accuracy is critical)
• The OHLC-only model should be limited to quick functional checks
• Always confirm data quality of 90% or higher before running a backtest

The accuracy of your backtest directly determines how much you can trust the results. When evaluating scalping EAs in particular, always verify using real tick data.

FAQ

Q: Where can I get real tick data?

The standard approach is to download it from the History Center while connected to your MT5 broker. You can only retrieve data within the range your broker provides. It is also possible to import CSV files from third-party tick data providers such as Dukascopy, but the import process into MT5 involves several manual steps and can be complex.

Q: Some currency pairs won't download at 99% quality — what should I do?

The range of historical tick data available varies by broker. Tick data older than around 10 years is simply not available from many brokers. In that case, start your verification from the earliest available date for that symbol.

Q: How do I keep backtest and forward test results consistent?

The fundamental approach is to run your forward test on the same broker account you used for the backtest. Because spreads and swap rates differ between brokers, using the same broker minimizes the divergence between backtest and forward test results.

Q: Does the Strategy Tester use the same model for optimization as for backtesting?

Yes. The parameter optimization process uses the same model as a regular backtest. However, because optimization runs thousands to tens of thousands of backtests, running optimization with the Every Tick model can take several days. The efficient approach is to run optimization using OHLC or 1-Minute OHLC, then perform the final validation run using Every Tick.

Related Pages

• Backtest Basics: Settings and How to Read Results
• Common Backtest Pitfalls
• Backtest Metrics Explained: PF, DD, and Sharpe Ratio
• GOLD EMA ATR EA — Official Backtest Details