Hi all!
For some context: I have been using a AMD Radeon RX Vega 64 for around a year now, and I am happy with it. It renders pretty fast and doesn’t get as hot as all the reviews said.
Recently I got the opportunity to buy a lightly used VEGA 56 for around 40€ (I know, sounds sketchy but it’s a friend of mine and I know that it works)
So, my question: Can I use them both in the same PC to render in Cycles? Is it possible that both render on the same frame?
Greetings from germany!
First… 40 E… WOWZERS… i wish I had firends like that 
Second, you can have many GPU’s in cycles. So far my biggest setup was 4 Vega GPUs. Working on upscaling that .
And yes single frame, each GPU gets its own Tile.
It is harder to get them to render different frames than the same frame. The easiest way to render different frames would be to split the frame number in half, open a new blender, open the file again, set the file number to half way through, hit render on both blenders. Or something with line code the two files could be saved and made to render on different cards so they would not be open taking up ram from blender being open 2x. Hope they officially add the option of different frames to blender in the future.
There is another way.
You still launch one Blender instance per GPU, but you set “set placeholder” and leave “override” disabled.
That way, first GPU starts rendering first frame, sets a “dummy file”
Second GPU tries to render first frame, can’t overrride the file, and starts rendering the next.
This way you dont’ end up with issues when first GPU finishes the first 1/2 while second GPU is till not done…
Works quite well.
I know it’s late an sort of a stupid question but please help me
can you please mention all the steps to get Vega 56 or any supported amd gpu to get working in cycles render
Do you have to install any specific drivers or frameworks etc
Any reply is appreciated
Thanks
And one more question will the upcoming cyclesX render engine replace cycles
It’s bugging me out since I have heard that cyclesX won’t support amd gpus
For Current Cycles, no extra drivers or anything is required.
BLENNDER → Edit → Preferences → System → OpenCL
At the top you’ll see various devices. Make sure to select OpenCL is selected, and the devices you want to use.
For CyclesX. currently there is ZERO support for AMD. They removed OpenCL. They are working with AMD and Intel to figure out a different way to use the GPU’s but nothing since that was mentioned.
There is a risk that 3.0 will be released with CyclesX without AMD support. Unfortunately AMD was for the longest time a secondary thought in overall development 
