It is pretty much the same isn't it, while the core power, as you correctly point out, is virtually doubled. I've made that very comparison, its same ballpark, just like your comment on 'its faster' and then pointing out percentile gaps on raster, I agree, that's the same perf on raster.
See and this kind of bullshit response from your end, is why you lose all credibility every time. Everyone with non hazy vision can see the problem in relative specs core to VRAM, except you.
And yet cache also turns into an achilles heel for even AMD at 4K where it drops off against Nvidia's 4090. At that point, they're saved (most of the time) by hard throughput being at 800GBps still on a 7900XT, to an extent.
Cache does NOT alleviate constraints in the very use cases where you need it most, which is with heavy swapping required due to large amounts of data needed at will. The two are at odds with one another. At that point you are saved somewhat by royal VRAM capacity.
Its a bit like 'I have super boost clocks' under loads where you already exceed useful FPS numbers by miles. Who cares?? Its nice for bench realities, in actual gaming, it doesn't amount to anything. This is where experience comes in. We've seen this all before and crippled bandwidth, real, hard, bandwidth, is and will always be a defining factor.
You put that 6600XT on a higher res, it will die horribly, whereas in relative sense the 1080ti would still be standing upright. I experience this now with a 1080 on 8GB, I can fill the framebuffer, FPS can go down, but the affair is still buttery smooth in frame times.