Improving Runtime speed on backtesting EA

[Sireatit]

I love MT5 along with it's MQL5, but I find it difficult to backtest any custom indicator. I initially thought it was a problem in the coding if the indicator, but even with the exact same indicator as those built in into their system being run as a custom indicator, the backtest slows down significantly. All the indicators that are preiny into the platform are great and all, but they are outdated. Is there a fix for this?