I recently had to make the same decision, wait for the new architectures or buy a flagship card now. I decided to go for it & got the 980ti in my sig. The way I looked at it was all we have are rumors for Pascal & some anecdotal evidence of Polaris right now. Neither will be hitting the supply chain till at least this summer probably later. We will most likely only see the low & mid range cards in the new architectures when they do finally release. Then most importantly we have no idea how good or bad these cards will be. We already seen HBM in the FuryX & Fury, TBH I wasn't too impressed with it considering the Fury X is just barely trading blows with the 980ti. If HBM was gonna be such a revelation I think we would've seen much better performance out of the FuryX/Fury. Don't get me wrong I do see HBM eventually making it's mark in the video card space but it is just not there yet & I do not expect HBM2 to be a massive leap over the HBM we can get right now.
If you really think about it even if the new dies are capable of blowing this current gen of GPUs completely out of the water what reasons would Nvidia or AMD have to release them at full power? That would essentially be a huge shift in the market & wipe out all the cards that came before it heavily cutting into both companies bottom line. I just do not see that happening unless AMD is even worse off than rumored & decides to go nuclear to try to save themselves. Also you have to think of how much ill will that would create with customers who can not afford to buy into the new architecture & would be left with severely under performing cards that are less than 2 yrs. old. It is a bad business decision no matter which way you look it.
IMO with so many unknowns & unsubstantiated rumors surrounding the next gen of GPUs you are best off to buy a high end card now that can last you through the release of the next gen. Then you can sit back & see what the performance gains will truly be, which manufacture has the better product, & have a wealth of information to base your next purchase off of. With Nvidia becoming more & more proprietary with what you can do with their cards & AMD teetering on the brink of destruction in the GPU market I am not willing to trust either of them TBH. With my 980ti I know I have a good product with good performance because I was able to use all the info from reviews & user feedback to ascertain that before I bought it. That will not be the case for at least a few months after the next gen GPUs release & if you have already been waiting months & months to complete a build I doubt you will want to wait even longer till a solid opinion of the new cards is formed. So the choices are grab something you can make an informed decision on now or wait to blindly grab a new product that may or may not be a leap forward in performance. To me the choice was clear, buy now then wait to see how the next gen shakes out before buying into that.
On top of all that you have to consider the way the products will be released too. AMD has pretty much confirmed that the 1st Polaris GPUs to get released will low end ones & Nvidia has the track record of doing the same. So even if we do see the next gen by this summer it will not be the flagship quality cards & I doubt any of them will exceed 980ti & FuryX performance. They might not even match that level of performance for all we know. The only way I would consider waiting on the next gen of GPUs to be released to a viable path would be if you already have a high end GPU that you are considering upgrading from. If you are currently building a PC waiting would be a waste of precious gaming/benching time IMHO. With high performance consumer PCs there will always be something bigger, better, & badder right around the corner & if you keep waiting on the latest & greatest you will never get your PC built let alone be able to enjoy it. At least that's my
on this subject.