Nvidia's 8xxx series was so good they're probably worried about the legendary that series carried. Actually some people still have 8 and 9 series cards, will this mean we'll get "AMD vs Nvidia, which 9series card should I get?"threads
I'm skeptical at the 512-bit Mem bus. Last card that had that was the 2900XT. And let's just say abject failure was a light way of describing it.
That was completely different. IIRC it used 2x256bit ring buses rather than point-to-point. I'm not 100% up to speed on this but the drivers weren't optimized for it and GDDR4 didn't scale as much as they expected to offset the latency. The same thing works for Intel in its LLC/Uncore these days though. The downside of 512bit buses is that it makes a MASSIVE die and your failure rate increases, unless, TSMC develop a suitably sized interposer. But Intel is the only one yet to attempt to commercialize it (if rumors be true) and not on the scale of a large GPU.
GTX 280 had a 512bit GDDR3 Bus, and that was a pretty awesome card at the time, personally suprised the Titan doesn't have one, but then again it was only s'posed to be the GTX 680. I can believe this, and frankly what they do after that with the consumer naming scheme is kinda trivial at the end of the day. Given the probable size of the die it's likely to not have it's full core count and/or aggressive clock speeds at least for the first gen. Same stuff different day.
That's really the real worry I have with 512-bit bus cards. The rarity of it with yields. If it is indeed on a a smaller process, expect paper launches everywhere. The GT200 and GT200b had very limited stock at the beginning and a rather high price tag as well. The only reason why it was lowered was that the RV770 chips were so much cheaper and amusingly almost as fast. They were undoubtedly good cards, but they were pretty scarce at the beginning. Almost as scarce as the GTX480s. I suppose with no GDDR6 or GDDR7 coming out, the expansion of memory buses is necessary. So It's basically 2008 all over again in terms of memory bandwidth.
GDDR5 will run for a while yet. Up to 9GHz they recon. I've not seen any musings on GDDR6/7 yet because the next step is interposers and WideIO not investment in future GDDRs. That's packaging, not DRAM.
