My experience with Intel ARC A310 Sparkle and Windows Server 2025 (Proxmox VM)

[kadargof 1]

My apologies if this topic is in wrong section. I just wanted to share my experience with A310 an WinServer 2025 (Proxmox VM), legacy host.

 

### [SUCCESS STORY]

 

Full Intel Arc A310 Hardware Encoding & Decoding inside Proxmox VM (Windows Server 2025 Guest) on Legacy non-UEFI Lenovo ThinkStation D20

 

I wanted to share a major troubleshooting victory for anyone trying to use an Intel Arc A310 GPU for media transcoding in an enterprise server environment.

 

Many guides claim that Intel Arc GPUs absolutely require modern UEFI and Resizable BAR (ReBAR) support to avoid crashing or hitting Code 43 errors. My setup proves that for specialized Emby video transcoding workloads, you can run an Arc A310 flawlessly on a legacy PCIe 2.0 system without UEFI or ReBAR options.

 

Furthermore, I hit the infamous Windows Server trap where the GPU would successfully handle **Decoding**, but **Preferred Hardware Encoders** would stubbornly revert to "Software Encoders." This was compounded by the fact that simply logging in via Microsoft Remote Desktop (RDP) would secretly hijack the driver and kill the encoders.

 

Here is the exact step-by-step blueprint to fix the missing frameworks, bypass the OS driver locks, and sandbox RDP so everything stays running perfectly in hardware 24/7.

 

---

 

### Phase 1: Motherboard & Hypervisor Base Setup

1. **Physical Loop:** Ensure a physical HDMI dummy plug dongle is firmly connected to the back of the Intel Arc A310 card. Headless server operating systems will refuse to initialize the encoding engine without an active display loop.

2. **Proxmox Passthrough:** Standard GPU passthrough rules apply. Ensure `iommu=pt` is enabled in your host boot options. Pass the card through to your Windows Server 2025 VM (Q35 machine type recommended).

 

---

 

### Phase 2: Forcing the Consumer Multimedia Frameworks

Windows Server 2025 strips out all consumer multimedia engines by default. This isolates background applications from the Direct3D11 runtime pipelines, causing Emby’s QuickSync initialization module to fail and return a `Result: null` error in your `hardware_detection.txt` logs.

 

1. **Install Media Foundation & .NET:** Open PowerShell as an Administrator inside the VM and execute:

```powershell

Install-WindowsFeature Server-Media-Foundation

```

 

 

Ensure you also navigate to Server Manager and install the required **.NET Framework features**. Restart the VM immediately.

2. **Install Legacy DirectX Runtimes:** Download the official offline *Microsoft DirectX End-User Runtimes (June 2010)* package. Extract it to a folder, right-click **`DXSETUP.exe`**, run it as Administrator, and complete the installation wizard.

3. **The Driver Bypass:** Do not run the standard Intel `.exe` installer wizard, as it actively blocks consumer encoding features upon detecting a Server OS. Instead, use 7-Zip to extract the Intel driver installer file into a normal folder on your desktop.

* Open **Device Manager**, right-click your Intel Arc display card, and choose **Update Driver**.

* Select **Browse my computer for drivers**, point it to your uncompressed folder, ensure **Include subfolders** is checked, and force-inject the raw driver files.

 

4. **The MediaSDK Registry Hack:** Create a file named `intel_fix.reg` on your desktop using Notepad, paste the following text, save it, and double-click to merge it:

```reg

Windows Registry Editor Version 5.00

 

[HKEY_LOCAL_MACHINE\SOFTWARE\Intel\MediaSDK]

"DispatchLevel"=dword:00000001

 

[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Intel\MediaSDK]

"DispatchLevel"=dword:00000001

 

[HKEY_LOCAL_MACHINE\SOFTWARE\Khronos\OpenCL\Vendors]

"intelocl64.dll"=dword:00000000

```

---

 

### Phase 3: Trapping RDP in a Software Sandbox

When you use native Microsoft Remote Desktop (RDP) to manage Windows Server, the OS stealthily detaches your Intel Arc driver and hooks up the *Microsoft Remote Display Adapter*. This instantly breaks Emby's access to the A310 hardware encoders.

 

To prevent RDP from stealing your GPU, force RDP to run strictly in a software-only rendering sandbox:

 

1. Press `Win + R`, type **`gpedit.msc`**, and enter the Local Group Policy Editor.

 

2. Navigate to: **Computer Configuration** ➔ **Administrative Templates** ➔ **Windows Components** ➔ **Remote Desktop Services** ➔ **Remote Desktop Session Host** ➔ **Remote Session Environment**.

 

 

 

 

3. Apply these exact policy configurations:

* **"Use the hardware default graphics adapter for all Remote Desktop Services sessions"** ➔ Set to **Disabled** *(Explicitly stops RDP from touching the Arc A310).*

* **"Prioritize H.264/AVC graphics mode for Remote Desktop Connections"** ➔ Set to **Disabled** *(Prevents RDP from spinning up the hardware encoding chips).*

* **"Use WDDM graphics display driver for Remote Desktop Connections"** ➔ Set to **Enabled** *(Forces RDP to act as a virtual shield using standard software rendering).*

4. Open Command Prompt as Administrator and run `gpupdate /force`, then restart your Windows Server 2025 VM.

 

---

 

### Phase 4: Finalizing Emby Configuration

1. Open Windows **Settings** ➔ **System** ➔ **Display** ➔ **Graphics**.

2. Click **Browse** under custom options and add both **`EmbyServer.exe`** (located under `%appdata%\Emby-Server\system`) and its encoder bin **`ffmpeg.exe`** (located under `%appdata%\Emby-Server\system\ffmpeg`). Set both executables to **High Performance (Intel Arc A310)**.

3. Open Windows Control Panel ➔ **Power Options** and switch your profile profile to **High Performance** to stop the server from aggressively parking the PCIe slots.

4. Exit the Emby desktop tray app entirely, clear the old hardware performance cache by deleting the `%appdata%\Emby-Server\programdata\cache\ffmpeg` folder, and restart Emby Server.

 

### The Verdict

Once Emby finishes compiling its new runtime shaders (you will see tiny Compute spikes on your GPU Task Manager graph), head to your Emby dashboard ➔ **Transcoding** ➔ **Advanced**.

 

Your **Preferred Hardware Encoders** will successfully list:

* `QuickSync Intel Arc A310 LP Graphics - H.264 (AVC)`

* `QuickSync Intel Arc A310 LP Graphics - H.265 (HEVC)`

 

You can now use your standard RDP windows to manage your server freely without losing hardware transcoding capabilities, achieving zero-buffer instant movie scrubbing on smart TVs paired with steady enterprise-class network file transfer speeds!

 

Edited Tuesday at 10:35 PM by kadargof
typo in the title

[Abobader 3505]

Hello kadargof,

** This is an auto reply **

Please wait for someone from staff support or our members to reply to you.

It's recommended to provide more info, as it explain in this thread:

Thank you.

Emby Team

[Luke 42735]

Hi, thanks for sharing. We will have anew ffmpeg build on the server beta channel very soon.

[kadargof 1]

Nice

[kadargof 1]

For better understanding...

[GUIDE] Intel Arc A310 Hardware Encoding & Decoding in Proxmox (Windows Server 2025 VM) on a Legacy BIOS System (No UEFI / No ReBAR)

Overview

After several days of troubleshooting, I successfully deployed an Intel Arc A310 LP GPU for full hardware decoding and encoding inside an Emby Server running in a Windows Server 2025 virtual machine hosted on Proxmox VE.
Many online guides suggest that Intel Arc GPUs require:

• UEFI firmware
• Resizable BAR (ReBAR)
• Modern PCIe platforms

to function correctly.
For my particular workload (Emby hardware transcoding), that was not the case.
This guide documents the complete process that ultimately resulted in stable hardware transcoding on the following legacy platform.

---

Tested Hardware

Host

• Lenovo ThinkStation D20
• Dual Intel Xeon X5680
• Legacy BIOS (no UEFI)
• PCIe 2.0
• Intel Arc A310 Low Profile
• Proxmox VE

Guest VM

• Windows Server 2025
• Q35 machine type
• GPU PCI passthrough

---

Initial Symptoms

Initially I observed the following behavior:

• https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/2705.png Intel Arc driver installed correctly
• https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/2705.png GPU detected by Windows
• https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/2705.png GPU passed through successfully
• https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/2705.png Hardware decoding worked
• https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/274c.png Preferred Hardware Encoders always reverted to Software Encoders
• https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/274c.png hardware_detection.txt contained Quick Sync initialization failures (Result: null)
• https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/274c.png Connecting through Microsoft Remote Desktop caused hardware encoding to stop working

Because the GPU itself was functioning correctly, the problem turned out not to be related to:

• Proxmox
• PCI passthrough
• Intel Arc drivers
• Legacy BIOS
• Missing ReBAR

Instead, the issue was caused by a combination of Windows Server multimedia components, driver installation behavior, and Remote Desktop graphics policies.

---

Phase 1 — Base Platform Preparation

1. HDMI Dummy Plug

In my environment, Windows Server would not consistently initialize the Intel Arc media engine while running completely headless.
Installing a simple HDMI dummy plug allowed the GPU to initialize correctly after every reboot.
Although this may not be required on every system, it was required in my configuration.

---

2. GPU Passthrough

Configure GPU passthrough normally.
Recommended configuration:

• IOMMU enabled
• iommu=pt
• Q35 virtual machine
• Intel Arc A310 passed directly to the guest

---

Phase 2 — Restore Windows Server Multimedia Components

Unlike Windows 11, Windows Server intentionally removes many multimedia features that consumer applications expect.
Without these components, Emby's Quick Sync detection failed and produced:
Result: null
inside:
hardware_detection.txt

---

Install Media Foundation

Open an elevated PowerShell window:
Install-WindowsFeature Server-Media-Foundation
Also install the required .NET Framework Features from Server Manager.
Restart Windows.

---

Install DirectX End-User Runtime

Download Microsoft's official:
DirectX End-User Runtimes (June 2010)
Extract the package and run:
DXSETUP.exe
as Administrator.

---

Phase 3 — Install the Intel Driver Correctly

The standard Intel installer detects Windows Server and may omit or block portions of the consumer multimedia stack.
Instead:

1. Extract the Intel driver package with 7-Zip.
2. Open Device Manager.
3. Update the Intel Arc device manually.
4. Browse to the extracted driver folder.
5. Enable Include subfolders.
6. Complete the installation.

This installs the raw driver without relying on Intel's installer logic.

---

Phase 4 — Media SDK Registry Configuration

Create:
intel_fix.reg
Paste:
Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Intel\MediaSDK]
"DispatchLevel"=dword:00000001

[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Intel\MediaSDK]
"DispatchLevel"=dword:00000001

[HKEY_LOCAL_MACHINE\SOFTWARE\Khronos\OpenCL\Vendors]
"intelocl64.dll"=dword:00000000
Merge the registry file.

---

Phase 5 — Prevent RDP from Taking Over the GPU

This ended up being one of the largest obstacles.
By default, Microsoft Remote Desktop may replace the active graphics adapter with the Microsoft Remote Display Adapter during remote sessions.
In my testing, this caused Emby to lose access to Intel hardware encoders even though the GPU driver remained installed.
To prevent this:
Open:
gpedit.msc
Navigate to:
Computer Configuration

Administrative Templates

Windows Components

Remote Desktop Services

Remote Desktop Session Host

Remote Session Environment
Configure:

Policy	Setting
Use the hardware default graphics adapter for all Remote Desktop Services sessions	Disabled
Prioritize H.264/AVC graphics mode for Remote Desktop Connections	Disabled
Use WDDM graphics display driver for Remote Desktop Connections	Enabled

Then run:
gpupdate /force
Restart the VM.

---

Phase 6 — Configure Emby

Inside Windows:
Settings

System

Display

Graphics
Assign High Performance to:
EmbyServer.exe
and
ffmpeg.exe
located in the Emby installation directory.

---

Switch Windows to the High-Performance power plan.
Finally:

1. Exit Emby completely.
2. Delete:

%appdata%\Emby-Server\programdata\cache\ffmpeg

1. Restart Emby Server.

---

Results

After Emby rebuilt its hardware detection cache, both hardware decoding and hardware encoding became available.
The Preferred Hardware Encoders list correctly displayed:

• Quick Sync Intel Arc A310 LP Graphics — H.264 (AVC)
• Quick Sync Intel Arc A310 LP Graphics — H.265 (HEVC)

Hardware transcoding continued to function correctly after:

• Multiple server reboots
• Multiple RDP sessions
• Normal day-to-day server administration

---

Final Notes

This guide documents one verified working configuration and should not be interpreted as proof that every Intel Arc deployment behaves identically.
However, it demonstrates that full Intel Arc A310 hardware transcoding is possible on a legacy BIOS platform without UEFI or Resizable BAR, provided that Windows Server's multimedia framework, graphics policies, and driver installation are configured appropriately.
I hope this saves someone else the many hours of troubleshooting that went into discovering these interactions.