BeamNG on three screens

Getting a picture on all three screens

The three hard requirements

BeamNG’s documentation says to use Borderless mode. On 0.39.4 that does not work, and this page says so on the strength of a rig it was tested against rather than on the strength of the docs. Use Window mode. The reasoning is in why borderless cannot span.

The feature is officially flagged “very experimental” and “may not work properly on certain setups”. That is BeamNG’s own wording, not a hedge added here. Treat a failure as a known rough edge rather than something you have misconfigured.

The identical-panel rule is stricter than it sounds. BeamNG splits its window into three equal thirds and assumes every monitor is the same width. A developer confirmed on the BeamNG.tech forum that differing resolutions are not supported and that there is no configuration file in which to describe per-monitor widths. On a mismatched rig, a 27 inch plus 34 inch plus 27 inch array for instance, the centre image comes out narrower than the centre panel and the side views spill onto its outer edges. No setting corrects this.

Arranging the displays in Windows

None of this is documented by BeamNG, so treat it as a list of things to rule out rather than a specification. Because the game sizes its own window across the desktop, anything that makes the three panels an irregular shape in Windows is a plausible cause of a failed span.

1. Put them in one straight row. Left, centre, right, in physical order, in Settings, System, Display.
2. Drag them flush. A few pixels of vertical offset makes the desktop bounding box taller than any one screen. Windows snaps if you drag slowly.
3. Match resolution and refresh rate on all three. A panel running a different mode is the same problem as a panel of a different size.
4. Set scaling to 100% on all three. Mixed DPI is the classic cause of a window that computes its own size wrongly, because the coordinates an application sees stop matching the pixels on the glass.
5. Make the centre panel primary. The menus and UI live on it, and it is the sane place for them.
6. Confirm Surround or Eyefinity is off. Windows should list three separate displays, not one wide one. If it lists one, the driver has already merged them and BeamNG has nothing left to span.

Window mode

Worth understanding before you pick, because BeamNG borderless is not what the name suggests in most games.

A BeamNG developer put the resolution behaviour plainly: the game has no render scaling, and “your resolution will match the game window, except in Fullscreen”. So borderless always renders at the full native pixel count of whatever it covers. That is why windowed across three panels is so punishing, and why there is no internal resolution slider to rescue you.

Renderer: D3D12, Vulkan, DX11

Choose from the BeamNG.drive launcher, or with a Steam launch option. This is the first thing to change if the span is not working.

If you are on Vulkan and Multi-Monitor Render will not span, change renderer before you change anything else. The BeamNG Vulkan troubleshooting page tells you to test Direct3D to establish whether a problem is Vulkan-specific, and stacking an experimental display feature on a non-default renderer is exactly the case that advice exists for.

Turning Multi-Monitor Render on

1. Launch on Direct3D 12 unless you have a specific reason not to.
2. In Options, Display, set the window mode to Window.
3. Tick Enable multi-monitor render.
4. Fill in the four fields. Despite the documentation calling them angle sliders, 0.39 asks for FOV: Monitor center / left / right fov in degrees all take the setup sheet’s per-screen horizontal FOV, and Monitor borders fov in degrees takes the angular width of one bezel seam. Setting a side FOV to zero disables that panel.
5. Press Apply. Nothing takes effect until you do, and it is the most commonly missed step.
6. Restart the game fully, not just the session, and check the result from inside a vehicle rather than from the menu.

The controls in this menu have moved between versions. 0.25 removed the angle, size and distance sliders and later builds restored some of them, so check what your build actually exposes before hunting for a field that is not there.

Why borderless cannot span

This is the part the official documentation gets wrong, so it is worth understanding rather than just following.

Multi-Monitor Render does not create the span. It divides whatever window it is handed into three frusta. Borderless sizes the window to a single monitor, so there is nothing to divide, and you get three narrow slices crammed onto one panel. Window mode is the only mode that lets the window cover all three.

Three independent observations on a working rig agree: the slices themselves, a forum report of identical symptoms on identical monitors following the documented steps, and the window visibly spanning for a moment at launch before being clamped back to one panel.

Getting the window exactly right

The window has to match the panel array exactly. Multi-Monitor Render splits it into three equal thirds and assumes each third lands on a panel, so a window 20 px too narrow or 8 px off the left edge misaligns every seam. Close is not good enough.

Work out your target rectangle first. If your centre panel is the Windows primary, its top-left is the origin, so the left panel sits at negative X. For three 3440x1440 panels that is -3440, 0, size 10320 x 1440. If your left panel is primary, it starts at 0, 0 instead.

1. Set Display Mode to Window.
2. Point the Monitor picker at the leftmost panel, so the window is anchored there and extends right across the other two. The picker’s numbering does not match Windows’ display numbers, so find it by trial: apply, restart, and see which panel the window lands on.
3. Use a window tool or a script to force the exact rectangle and strip the title bar. BeamNG always draws one in Window mode and sizes itself to the desktop work area, so the taskbar stays visible otherwise. Neither is fixable in the game.

WindowPlacement in the settings file is an output, not an input. The game rewrites it on every boot, so editing it achieves nothing. Its format, if you need to read it, is flags showCmd minX minY maxX maxY left top bottom right, where showCmd 3 means maximized and 1 means normal. A maximized window can only ever cover one monitor.

The settings file

Under %LOCALAPPDATA%BeamNG.drive, in your version’s settings folder, game-settings.json holds the values worth knowing. Edit it with the game closed, since it is rewritten on exit, and keep a copy.

If it spans but the seams look wrong, that is a different problem. That is angle and FOV, and the setup sheet covers it: the per-screen horizontal figure goes into the game, and the tape-measure helper gets your physical angle to match the number you told it.

Making it run

Why triples cost three scene passes

The important thing about BeamNG triple mode is that it is not one wide view. It is three separate views with their own frusta, which is exactly why the geometry comes out correct at the seams, and exactly why it is expensive. The scene is culled and submitted three times per frame, not once.

That splits the cost across two budgets which behave very differently. The GPU pays for roughly three panels worth of pixels. The CPU pays for roughly three times the culling and draw-call submission, and BeamNG already asks a lot of the CPU because its physics run there. On most triple rigs the CPU is what runs out first.

VRAM is the wall you hit first

On a rig measured for this page, a 16 GB RTX 5080 driving 14.86 megapixels ran out of video memory entirely: 0.0 GiB free, GPU time 62.9 ms, and the CPU spending 50.8 ms of every frame parked in WaitForGPU. That is the driver paging textures over PCIe, and it costs far more than any setting saves. BeamNG’s own Direct3D 12 page warns that running out of VRAM causes severe slowdowns, blurry textures and graphical errors.

Deferred rendering is why. Every full-screen buffer at 10320x1440 is around 59 MB, and a deferred renderer keeps a lot of them. Texture Quality, shadow maps and reflection targets all come out of the same pool.

Restart the game after every graphics change. BeamNG does not release the old render targets and texture pools when you change quality live, it allocates the new ones alongside. At triple resolution each of those is huge, so a tuning session slides steadily toward zero free VRAM and your framerate gets worse the more you optimise. On one screen you would never notice.

Watch Available GPU memory in the performance overlay rather than guessing. Under a gigabyte free means nothing else you change will matter until you free some.

Pixel maths

Total pixels are width times height times three. A single 4K screen is shown for scale, since that is the workload most benchmark numbers describe.

Settings that actually move it

Grouped by which budget they come out of, because that determines whether they will help you at all.

If you are already on the Low or Lowest preset, dynamic reflections and mirrors are disabled for you already, so the usual advice to turn them off is spent. Normal is the preset that turns mirrors back on. Once those are gone the remaining levers are traffic, vehicle count and getting out of windowed mode, not the graphics preset.

Before tuning anything, check which budget you are actually short of. Watch GPU utilisation during a frame drop. Pinned near 100% means the pixels are the problem and the presets will help. Sitting well below it means you are CPU-bound, and lowering visual quality will not do much.

What no setting can fix

Two limits are structural, so they are worth knowing before you spend an evening on sliders.

Curved panels. BeamNG projects onto three flat planes. If your monitors are curved, an 800R or 1000R panel for instance, the image is correct for a flat screen of that width and the curvature adds distortion that no FOV or angle value removes. Tighter curves make it worse. The plan view on the setup sheet models your actual curvature, so you can see how much of the panel is affected.

Mismatched monitors. The equal-thirds split is baked in. Different widths or resolutions misalign the seams and there is no configuration file to tell the game otherwise. If your side panels differ from your centre, native triple render is not going to give you a correct image.

Sources

Everything quoted or specified comes from these. Where this page goes beyond them it says so, and where it contradicts them it says that too.

The largest disagreement is window mode. BeamNG’s documentation says to use Borderless. Tested against 0.39.4 on three identical 3440x1440 panels, Borderless clamps the window to one monitor and Multi-Monitor Render then slices that single panel into three. Window mode is what actually spans. The documentation also describes the sliders as angle controls; in 0.39 they are FOV fields.

• Multi-Monitor Render and the support portal version of the same page. Requirements, the Apply Display Settings step, the experimental warning.
• Direct3D 12 Renderer. D3D12 as the Windows default from 0.39, DX11 as an obsolete fallback.
• Vulkan Renderer. The status of Vulkan on Windows, and the advice to test Direct3D to isolate a Vulkan-specific fault.
• Arguments and Settings. The -gfx flags.
• Configuring triple monitors of different sizes. The developer statement on equal thirds and unsupported mixed resolutions.