Yes i know AMD stopped supporting CFX on their RX 5000 series, and yes i know my CFX Vega 56's are smoked by even a RX 5700 these days. This isn't me asking/demanding/crying for AMD to reverse course on their business decisions, but i was honestly pretty stunned at the sheer lack of any information on the current state of CFX.
With all those concessions out of the way i can get to the meat of this entire post, and why i'm making it. This computer i built several years ago specifically for Crossfire, it's a big, beefy full-tower case that supports 2 PSUs that i have connected via the wonderful ADD2PSU relay since i didn't trust my own handiwork for the output of two PSU that could make a decent attempt at arc welding with their single 12v 50a rails. (They're both EVGA make, 1000W so high-quality stuff here)
I had a series of hardware issues in the distant past that lead to me RMA'ng both GPU, and in the meantime i got busy and never installed the second for a while. Today i decided that i'd like to get my rig fully operational again and plunked my second GPU in and clipped in the 8 and 6 pin connectors.
I DDU'd the drivers, and reinstalled. She POSTed and there were no immediate issues, as both GPU were detected and CFX enabled without a hitch. And then i decided to play a game....
For the next 4+ hours i encountered nothing but "thread_stuck_in_device_driver" BSODs whenever i even attempted to use the GPUs in CFX...even GPU-Z;'s full screen "Render test" reliably caused the BSOD.
I DDU'd Again, when that failed i updated the BIOS ( a Longshot because i knew this system ran CFX before), and when that all failed me again, reinstalled windows, and only after all of that nonsense i decided to dredge up Radeon Software 18.7.1 from 2019 , since all the drivers from 2022, 2021 and 2020 would not work.
DDU'd, installed the legacy driver and bam it just worked...
CFX is temperamental at the best of times, and it DOES require some patience and understanding to make work on a regular basis. But I've seen multiple posts (Some even from this forum) saying that this is normal and expected behavior...
It's not, CFX might cause games to have massive stuttering, terrain and environment flickering, negative scaling ,etc.
But BSOD's aren't normal for a game "Just not supporting" a driver feature, and in the worst cases the game will (should) just crash. So if you're one of the 3 people out there still running CFX and encounter this issue? Hopefully this might save you some frustration.
Specs -
CPU - Ryzen 1700 @3.00Ghz (stock)
MOBO - AsRock Taichi Ultimate X470
RAM 32GB DDR4 @2133mhz
GPU(s) - 2x Powercolor Vega 56 Red Dragon
PSU - 2x EVGA Supernova GQ 1000W (one for the GPUs and another for the system)
Drive(s)
Boot - 256GB Sata SSD
Data - 2TB 5400RPM HDD, 3TB 7400RPM HDD
