> Even if the 12GB 4080 manages twice the performance of the 3070, at nearly twice the price, that doesn't make it better value.
I'm not a GPU expert: what other characteristics other than performance are there to consider when deciding value? Intuitively, it seems like if something is twice the performance and less than twice the price, it is a great value.
For instance, suppose some not-too-demanding game runs, at quality settings you find satisfactory, at 50fps with one GPU and at 100fps with another. You are not going to enjoy playing at 100fps twice as much as you enjoy playing at 50fps.
Suppose it's 20fps versus 40fps. Playing at 20fps might be a horrible enough experience that 40fps really is twice as enjoyable; but in that case you probably won't play at 20fps, you'll turn some settings down so that everything looks a little fuzzier or the reflections aren't as realistic or something. You'll get a worse experience with the worse-performing GPU, but again it's unlikely that you enjoy your games half as much.
Even if you are doing something, like training neural networks, for which twice the performance really does translate into twice as much benefit in some meaningful sense, that's not necessarily the same thing as "worth twice as much money". It might be worth more than that (now you can train the NN you're working on in time to get a paper into that important conference, and before you couldn't). It might be worth less (training neural networks isn't a large fraction of what you do and you don't really care much how fast it happens).
Analogies: A car that can drive at 200mph isn't worth 2x as much as one that can do "only" 100mph, to most people; to a racing driver it might be worth a lot more than 2x. An oven that can heat things up to 600 degC isn't worth 2x as much as one that can reach "only" 300 degC, to most people; to a pizza chef, it might be worth a lot more than 2x.
It's not a great value when it's nearly twice the price and double the performance two years later. It has been reasonably common to get 50% or more performance increase between generations for the same price, and rebranding a XX70 as a "4080 12GB" to increase the price doesn't change that. It's also unusual for a XX80 to be "nearly double the price" even a generation later.
The pricing is out of line with what would historically be expected, as is having a completely different die.