How to use multiple monitors, independently??

[Gorlash 0]

I'm using Windows 10 ( Windows 10 [Version 6.3.19045]) still; I just got a second monitor, and wanted to use it to do other things when playing a game, such as monitor email, or operate a training program.

So I brought it online, it came up as Desktop 2, showing the same screen as as Desktop 1...

What I was *expecting* to do, is either:

start a program on D1, then drag it to D2, or

Move the cursor over to D2 and start a program over there...

However, I can't figure out how to actually make this work??

If I set the display mode to Extend, I can drag a program from D1 to D2, and move the mouse back and forth between them... however, I can't run the games that way; at least Assassin's Creed Shadows doesn't work - it just fails with a DX12 error... I'm guessing it thinks the total display area is area(D1) + area(D2) ...

However, none of the other Multiple Displays options actually allows me to both monitors independently...

Is there some way I can keep the Desktops separate, and switch back and forth between them??

[Trevor Neale 0]

What Windows Is Actually Doing

When you plug in a second monitor, Windows gives you three basic options:

Duplicate: both screens show the same thing — what you saw by default.

Extend: one large desktop spread across both displays.

Second screen only: turns off your main display and uses the second one.

What Windows doesn’t support natively is true “independent desktops,” where each monitor runs its own apps, with separate full-screen control or GPU contexts. In other words, the OS and DirectX see one unified graphics surface when in Extend mode — so when you launch a full-screen DX12 game, it thinks it needs to render across the combined resolution (which is why Assassin’s Creed crashes).

🕹️ Why the Game Fails

Most modern games, especially in exclusive full-screen mode, don’t play nicely with multiple monitors if they’re extended.
They expect to “own” the GPU’s primary display output.
When the desktop is extended, the total resolution becomes something like 3840×1080, and DirectX 12 tries to allocate a render surface that large. Boom — DX12 error.

🧩 Workarounds That Actually Work
1. Use Windowed or Borderless Window Mode

Most modern titles, including Assassin’s Creed, have a “Borderless Windowed” mode in their graphics settings.
That lets the game fill your main monitor but still keeps the OS aware of your second screen — so you can:

Move the mouse to the other screen,

Open email or a browser there,

And alt-tab without your game minimizing.

If you can, switch to that mode — it’s the easiest fix.

2. Use Two Separate GPUs (or GPU + iGPU)

If your PC has:

A discrete GPU (e.g., NVIDIA/AMD), and

An integrated GPU (Intel HD/Arc),

You can connect one monitor to each, then disable “Extend” entirely.
Each GPU then runs its own display pipeline.
You can’t drag windows between them — they’re separate — but you can run a game on one GPU and have your desktop active on the other.

It’s clunkier but closer to what you described: “two independent desktops.”

3. Virtual Desktops (sort of helpful)

Windows 10’s “Task View” (Win+Tab) lets you switch between virtual desktops, but they all share the same monitors — you can’t pin one desktop per monitor. So it doesn’t solve your problem, but it’s worth knowing.

4. Third-Party Tools

Some advanced setups use:

Actual Multiple Monitors, or

DisplayFusion, or

Ultramon

These give you more granular control over how apps behave on multi-monitor systems — e.g., locking a taskbar and set of shortcuts per screen — but they still can’t bypass the DX12 full-screen limitation.

5. Use a Second Machine

If your goal is “play on one, monitor things on another,” the cleanest path is often using a second PC, laptop, or even a tablet on the side. Tools like:

Remote Desktop,

Input Director, or

Barrier (open-source KVM)

let you share mouse and keyboard between systems seamlessly.

🧭 TL;DR

Windows can’t truly run “independent” desktops per monitor under one session.
But:

Use Borderless Windowed for games.

Or, connect each monitor to a separate GPU (if available).

Or, use another device for multitasking.