Comment by trod1234

I feel like this issue is to at least some extent a red herring. Even accepting that ROCm doesn't work on some motherboards, this can't explain why so few of AMD's GPUs have official ROCm support.

I notice that at one point there was a ROCm release which said it didn't require atomics for gfx9 GPUs, but the requirement was reintroduced in a later version of ROCm. Not sure what happened there but this seems to suggest AMD might have had a workaround at some point (though possibly it didn't work).

If this really is due to patent issues AMD can likely afford to licence or cross-license the patent given potential upside.

It would be in line with other decisions taken by AMD if they took this decision because it works well with their datacentre/high-end GPUs, and they don't (or didn't) really care about offering GPGPU to the mass/consumer GPU market.

FYI AMD also has similar "accelerators", with the 9070 having separate ALU paths for wmma ("tensor") operations much like Nvidia's model - older RDNA2/3 architectures had accelerated instructions but used the "normal" shader ALUs, if a bit beefed up and tweaked to support multiple smaller data types. And CUDA cores are just what Nvidia call their normal shader cores. Pretty much every subunit on a geforce has a direct equivalent on a radeon - they might be faster/slower or more/less capable, but they're there and often at an extremely similar level of the design.

AMD also have on-die microcontrollers (multiple, actually) that do things like scheduling or pipeline management, again just like Nvidia's GSP. It's been able to schedule new work on-GPU with zero host system involvement since the original GCN, something that Nvidia advertise as "new" with them introducing their GSP (which just replaced a slightly older, slightly less capable controller rather than being /completely/ new too)

The problem is that AMD are a software follower right now - after decades of under-investment they're behind on the treadmill just trying to keep up, so when the Next Big Thing inevitably pops up they're still busy polishing off the Last Big Thing.

I've always seen AMD as a hardware company, with the "build it and they will come" approach - which seems to have worked for the big supercomputers who likely find it worth investing in their own modified stack to get that last few %, but clearly falls down selling to "mere" professionals. Nvidia, however, support the same software APIs on even the lowest end hardware, while nobody is likely running much on their laptop's 3050m in anger, it offers a super easy on-ramp for developers - and it's easy to mistake familiarity with superiority - you already know to avoid the warts so you don't get burned by them. And believe me, CUDA has plenty of warts.

And marketing - remember "Technical Marketing" is still marketing - and to this day lots of people believe that the marketing name for something, or branding a feature, implies anything about the underlying architecture design - go to an "enthusiast" forum and you'll easily find people claiming that because Nvidia call their accelerator a "core" means it's somehow superior/better/"more accelerated" than the direct equivalent on a competitor, or actually believe that it just doesn't support hardware video encoding as it "Doesn't Have NVENC" (again, GCN with video encoding was released before a Geforce with NVENC). Same with branding - AMD hardware can already read the display block's state and timestamp in-shader, but Everyone Knows Nvidia Introduced "Flip Metering" With Blackwell!