They use different technology for their VRAM though. Apple, AMD Strix and NVidia DGX/RTX Spark use LPDDR, whereas discrete cards will be either GDDR or HBM. That directly impacts the memory bandwidth figures. As for compute available, Apple and AMD still have very good figures there for what's essentially a general-purpose iGPU that ships as part of the stock system, rather than a special-purpose piece of dedicated hardware.

There’s something else. Memory size.

Even if a Mac isn’t the fastest in raw numbers it may be faster if it can load the whole model in its ram (went up to 512 GB before shortages) than a couple 32 GB cards could with the data having to be constantly loaded over PCI-E. Because unified memory means the Apple GPUs can access all 512 GB at full speed.

My understanding is this is the advantage that’s pushing huge Mac Studio demand. Because it was the only way to give GPUs so much memory at price points anywhere near.

Yeah you can do way better once you’re in the 5 digits. But below that Apple had a specific advantage for some.