Hell Let Loose: Vietnam tank and AMD GPU crashes: launch options that help

Team17 says tank crashes are escalated and tells players to add -dx12 -USEALLAVAILABLECORES -malloc=system to the Steam launch options; what that is and what it does not fix.

Answer: Team17 says tank crashes are escalated and asks players to add "-dx12 -USEALLAVAILABLECORES -malloc=system" to the Steam launch options. The -malloc=system flag switches the Unreal Engine 5 allocator to the Windows system heap. It is a workaround, not a confirmed fix.

Version scope

Team17 support replies read 21 Oct 2026 · a workaround, not a confirmed fix

Game status

Released

Platforms

PC

Hub directory

Hell Let Loose: Vietnam

Verified

2026-10-21

Updated

2026-10-21

What the developer says

A player posted in the game's own "Report a Problem" forum that they crash almost every time in a tank. Team17 support replied that they have received reports of the same issue from other players, that it has been escalated to the team, and that in the meantime players should try the following launch options:

`` -dx12 -USEALLAVAILABLECORES -malloc=system ``

That reply is the current first-party position: the crash is known and being looked at, and there is a specific thing to try while that happens.

What each flag is for

• -dx12 selects the DirectX 12 renderer explicitly.
• -USEALLAVAILABLECORES stops the engine from assuming a fixed CPU core count.
• -malloc=system makes Unreal Engine 5 use the Windows system heap instead of its own bundled allocator. A player in the same thread reports that this "worked a bit and increased FPS by about 30+", and another adds that it is the flag that made the game stop closing with a GPU error after firing a tank gun. The developer does not publish an explanation of the flag, so the frame-rate claim is a player report, not a benchmark.

Where to put them

In Steam: right-click Hell Let Loose: Vietnam in your library, choose Properties, then Launch Options, and paste the three flags separated by spaces. Start the game from Steam again so they take effect.

What this does not fix

• It is a workaround for one crash class, not a fix. The developer says the issue is still under investigation, and no patch is named for it.
• It does not address the separate "failed to load user data" loop, which has its own published steps on the Epic sign-in and user data page.
• It does not cover keybinding behaviour, which the publisher tracks separately — see keybinds and controller customisation.
• We did not test these flags ourselves, and no frame-rate or crash-rate figure here is a measurement by this site.

Related official reading

The same "Report a Problem" forum holds the other crash and input reports. The publisher's own dated status on input issues is tracked in its regular Community Feedback posts, which the keybinds page summarises with dates.