It has long been a common issue for Vega cards on classical Mac (4,1/5,1) with opencore: the fan is not spinning fast enough on idle, leading to high temperature (~75'C). In many posts, it is assumed to be acceptable, and was advised to do nothing. However, it is just too hot!
I have mac pro 5,1 with opencore legacy patcher and I have been suffering this problem for long time. The card is able to heat my small bedroom in winter!
I tried different SMBIOS through changing board-id (For Monterey on Mac Pro, you may pick between iMac Pro1,1 or MacPro7,1). It does change the way the fan behave. For example, with the default set mac pro 7,1, boot loader does not load graphic acceleration and vram clock/fan speed management, until a graphical accelerated app is launched; while changing to iMacPro1,1, the card will be kept at low performance all the time, even under high loading of GPU demand. The problem arise from the fundamental difference of the power management and how fan was controlled through the hardware (On iMac Pro 1,1, there is likely no GPU fan, and the ventilation is controlled by the system fan.)
However, I finally solved the problem with a solution that has been exist for years, a power play table generated with VGTab tools developed by lihaoyun6 in 2019 (
https://www.tonymacx86.com/threads/...a-in-macos-without-flashing-the-vbios.268965/)
Download the tool, run it on your hack, change the target temperature to 50'C, get the VegaTab_64,kext, put it into your opencore build (EFI/OC/kexts), add the item into your config.plist and reboot. Boom! You mac will keep the card cool on idle and in high performance on high load.
I really hope the developer of opencore legacy patcher include the VegaTab_64.kext in their package. It will save a lot time for many people like me. For anyone in similar situation with me, you may try the attached kext if you do not want bother downloading the tool. Remember that the target temperature is set to 50'C in my kext. If you want to change it, go to here to download the tool:
Now you can control your Vega on macOS without flashing the vBios As we know, the Vega graphics cards have native support in macOS HighSierra and Mojave. emmm...and some glitch :( But AMD uses a function called "SoftPowerPlayTable" to control the Vega cards. "Soft" means it can be stored in the...
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