MT4 or MT5 for scalping, where it actually changes things

[Shadow Trader]

Platform arguments get religious fast, so here's a plain side-by-side of the bits that touch a scalper.

MT4 has nine timeframes and nothing between M1 and M5. No 2 or 3 minute chart unless an indicator fakes one. MT5 adds M2, M3, M4, M10 and more, which matters if a setup lives on the 3-minute chart. Anyone running a 3-minute strategy on MT4 is already using a workaround.

Order handling differs. MT4 accounts are typically hedging, where a buy and a sell on the same pair sit as separate tickets. MT5 started out netting only, with hedging added later, and what an account gets depends on how the broker set it up. Netting merges positions, so a scale-in becomes one average price and one stop. Some scalpers like that. Others hate losing separate tickets.

The tester is the big one. MT5's tester can run on real ticks and spread work across several cores, while MT4's is single-threaded and works from generated ticks unless data is imported. Faster optimization isn't the same as better results, though.

Execution settings differ too. MT5 exposes fill policies such as fill-or-kill and immediate-or-cancel, plus market depth where the broker provides it. In FX that depth is often just the broker's own view, so don't expect a real order book.

The ecosystem lag is real as well. MT4 still has the bigger pile of legacy indicators and EAs, and MT5 needs code ported across, since MQL4 and MQL5 are not the same language.

None of this crowns a winner. A 1-minute scalper on a hedging account with stock indicators may notice almost nothing, while a systematic trader testing 3-minute logic will notice a lot.

Which one do you scalp on, and what single feature decided it?