Let me preface my bullshit by saying that I’m not a hardware expert within even Tolkien’s stretched imagination, so feel free to correct me where I’m wrong.
Past evidence would seem to indicate that AMD cards pick up somewhere between 10 and 15 percent in performance over their lifespans through driver improvements when compared to their nVidia competitors (from the same generation). We have already seen measurable, if not eye-catching, improvements in the Polaris line of cards from their initial launch. With the amount of hype leading up to this launch (largely perpetuated by AMD), a certain level of performance will need to be met by AMD at launch (roughly 1080 level at a similar price from what I’ve been hearing) or face a serious backlash from the consumers. Would it be a stretch to assume that the driver team from AMD has been focusing solely on Vega’s performance? I don’t think so.
With that in mind, I expect 1080 class performance at launch with subsequent patches letting it split the difference between the 1080 and 1080ti. I don’t think they are going to be able to fully recognize all of the performance the Vega chip can provide because, in AMD’s own words, it is very big change to the GCN architecture.
I think that in 18 months to 2 years after its launch, it will be beating (That might be too strong… how about competing with) the 1080ti. I might be reaching a little too much, but looking at the on-paper specs of the card, it easily competes at the 1080ti/TitanBS level. The biggest challenge the card faces is driver support, which is not something that AMD has excelled at. They have made strides in that area, but I think that hoping to have a 1080ti killer out of the gate is absurd.
Will AMD be able to produce the GPU/HBM/interposer package cheap enough for it to be a compelling option? No idea. It’s a big chip, the HBM system is not easy, or cheap, to produce. I don’t worry about the performance as much as I do the cost. I think it’s 2kliksphilip who says that there is no such thing as a bad GPU, only a bad price.