As of no difference in compute workloads, I can put Blender as an example: https://techgage.com/article/blender-2-91-best-cpus-gpus-for...
(6900 XT is 20.6 TFLOPS FP32, RTX 3090 is 35.6 TFLOPS FP32 _and_ also has the tensor cores, AMD can't win there because of sheer brute force)
And AMD's software stack removes them from consideration for a huge extent of compute workloads. If they aren't ready to have a proper one, it doesn't matter how good how much their hardware is good or not, it might as well be a brick.
Either way, CUDA should be gone for good and replaced with something that's not tied to specific GPU. I welcome competition in hardware. I have no respect for lock-in shenanigans.
I wish CUDA wasn’t vendor locked, too, but AMD and Intel need to start taking GPGPU software seriously. They’ve dug themselves a massive hole at this point.
RDNA2 with its cache and low main memory bandwidth didn't help either, because while the cache is there, you're going to exceed what it can absorb by a lot in compute workloads...