PC Graphics

[Kairodar]

I am attempting to crossfire 2 RX 7900 XTX cards. I have the ASRock X670E Taichi AM5 EATX Motherboard with the AMD Ryzen™ 9 7950X3D 16-Core, 32-Thread Desktop Processor. I have installed the drivers and the software is not giving me the option to enable crossfire. Any insight on how to rectify is appreciated. 

[elstaci · Accepted solution]

AMD doesn't support Crossfire anymore for several years now. Crossfire was replaced by MGPU technology: https://www.amd.com/en/support/kb/faq/dh3-018

Overview

AMD MGPU technology harnesses the power of two or more discrete graphics cards working in parallel to dramatically improve performance in games and applications. On systems with AMD MGPU enabled the video output is delivered through the primary GPU and the workload is allocated to all supported GPUs in the setup.

Multi-GPU support and performance varies by applications and graphics APIs. For example, games/applications using DirectX® 9, 10, 11 and OpenGL must run in exclusive full-screen mode to take advantage of AMD MGPU. For DirectX® 12 and Vulkan® titles, multi-GPU operation is exclusively handled by the application and configured from the in-app/game menu for graphics/video.

Note: The steps outlined below are based on AMD Software: Adrenalin Edition 22.3.1 (Full Install) and the screenshot used are for illustrative purposes only. Depending on your system configuration, some options and settings may not be available to you or exactly as shown in the examples provided.

NOTE: Also games or apps must support Crossfire for it to work.

[amite]

Try some old drivers for fun

AMD Radeon Software Crimson Edition 16.4.2

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[OGoverclocked]

Any luck? I'm really considering doing this

[Earnhardt]

Don't, The last real Crossfire that worked was the old HD7970 series, It worked great then, But now its overpriced and better with a single card, AMD and most games no longer support Crossfire.

[greorycho]

I installed 2x 7900 XTX in my old PC with rossfireX support in PCI-E x16 slots.  Strangely the video outputs on the first one stopped working after adding second one. I use linux and all happened under Ubuntu 22.04. I could only use second GPU output. At the time (2 days ago) I didn't know that this is probably the way it works. Out of couriosity I swapped the cards in the slots and the both cards stopped working. I checked on different PC individually each card with no success. It's a bummer I thoutght I will share  it to warn anybody. For me it looks like bios (old motherboard with non-uefi BIOS) disabled the outputh of the graphic cards but it doesn't turn it back on when only one card is plugged in. Both cards are on warranty and I will probably send them back. I tried almost everything, even installed Windows 10 on my spare card (ATI HD 5770) and then plugged in one of the 7900 XTX into second PCI-E slot but no results. Windows doesn't see it, drivers installer doesn't see it. If you have any ideas let me know. I reflashed BIOS but nothing happened.