Keep in mind that Crossfire/DX11 and mGPU/DX12 support is also dependent on the game(s) itself. Anyway, with that said your Firestrike result is pretty low. This is not typical as you can see from other single Radeon RX Vega 64 results posted here: AMD Red Team 3DMark Scoreboard (see results in the Firestrike section by sgtbilko and kxuping
Since I don't know what kind of settings you're running it could be a number of things happening:
1. You GPUs are thottling due to heat issues - what are your fan settings like? (post a pic of your Radeon Settings config for your cards)
2. Try using a custom profile and JUST maximize the Power settings
As for the first GPU tach not lighting up during that benchmark is also odd; it could be an indication that something is wrong that card, or your drivers may need to be (re)installed properly. Try an updated DDU and run it from safe mode. While you're at it, temporarily disable ANY other app you use to OC/modify your GPU settings.
i have exact same issue, also one tachometer is only at 1, the only thing i noticed is that the bios on one of the cards is newer
As with the original poster, try posting some screenshots or provide more information unless you have the exact same issues and hardware.
Anyway, try to completely uninstall the old driver (most current version of DDU in Safe Mode or the "Clean Install" option in the Radeon Crimson app) before reinstalling the latest version greater than 17.9.2.
Just got a second Vega. Now I can try mGPU as is called now. Will post if it works or not for me.
Hey has anyone got this working? I just got 2 Asus strix RX Vega 64's and they only work with 1 card. Like it says the crossfire logo in games, but no matter what settings or profiles I use the game either freaks out with flickering or crashes all together. The only game I got it working on the Witcher 3 but even then it would drastically drop from 90FPS to 40FPS (running in 4k with high to highest settings, and even tested on lower settings). Also one card would be utilised 99% whilst the other says 1% - 20%, and one card hits 85 Degrees celcius whilst the other is at 35. When I use one card it sits near 70 - 75 Degrees. I haven't done much overclocking really, just undervolted and raised power limit, also increased fan speed to 800rpm - 3200rpm. I also tried stock settings with increased fan, and stock in general. There's a switch on the card to switch from a more powerful mode to a "quieter" mode, am I supposed to flick that on to quiet?
Any help would be gratefully appreciated!
P.S. when the game crashes sometimes the drivers crash, but that's due to overheating, other times the game crashes and both cards are at 40 degrees.