Long time lurker, long time PC enthusiast (long before 2010).
Given the discussions of 4gb vs. 8gb 480's, I thought some might find the following to be of interest (because it's mostly been ignored in the thread until the last few posts). At bottom, the 4gb exists only to sell the 8gb version to maximize AMD income & marketing mindshare. It's all about consumer psychology. I would suggest that >70% of the 480s manufactured will be 8gb models b/c significant research by AMD has surely confirmed that the overwhelming number of consumers will end up purchasing the 8gb model as explained below.
The pricing of, and difference between, the 4gb and 8gb versions of the 480 exists to upsell consumers to the 8gb version. For those interested in the strategy, it's referred to as "decoy pricing." For the most straight-forward example, see
http://www.realcasestories.com/2016/02/decoy-effect-popcorn-pricing.html for a brief discussion of a study conducted concerning movie theater popcorn pricing. Most are familiar with this strategy in movie theaters where the "large" size is priced to attract purchasers even though the quantity is unnecessary and the price differential still excessive to justify the true additional value provided (not that I'm saying that applies to the 4gb/8gb - but the theory is the same).
Although the "decoy pricing" technique frequently involves 3 pricing tiers (as discussed in article above), it can equally be applied here, where there are only two tiers but the prices between the tiers versus the perceived benefits are minimal.
The 480 4gb will be priced at $200. This is the anchor price that sets the overarching market tier of the 480 series. But, it's not the product that AMD really wants to sell. Instead, AMD prefers to maximize revenue, profits (& mindshare but that's a different issue from pricing strategy and I don't want to digress). Welcome, the 480 8gb for but a mere $30 more. Why $30 more? Because the purpose isn't really to highlight a huge technical discrepancy between 4gb vs 8gb that would call people to really examine the issue of 4gb vs 8gb. It's a non-winner (for the aforesaid reason that at this time and near future 4gb is sufficient and b/c it would have a negative effect on the overarching marketing tier ($200 & below with the 4gb 480, 470 & 460)). The purpose is to provide a low barrier incentive to get people to spend more than they really need. AMD realizes that a gamer purchasing a $200 card is unlikely to immediately discount the option of spending $30 more for a perceived benefit (4gb more VRAM) whereas $50 or $70 may. Thus the gamer will consider the upsell depending on the bait ("perceived value") of the upsell. For the decoy pricing to work, the "perceived value" must be greater than the cost of obtaining the perceived value.
We know the cost. How strong is the perceived value/benefit?
(1) Future Proofing - Few want to purchase within their tier thinking that their investment is already of questionable value or will be short-lived. And, believe it or not, it's an important emotional aspect of electronics purchases. With but a slight increase in price ($30) one can future proof their 480 video card to ensure that VRAM limits won't get in the way any time soon. For $30, that's quite a bit of piece of mind.
(2) Top Level Purchase - Within a purchasing tier, many prefer to first eye the top of the offerings within a tier. In this case that's the 480. Having decided to consider the top offering, one is more likely to consider "options" that go along with the top tier so as to ensure they've maximized their choice. In this case, if you're going to buy the top-tier of the market segment, you can spend an extra $30 and ensure that you have the best of the best of that teir. For $30, you just got the best!!!!!!! What a cheap price to pay (again, some of the statements I am making reflect the emotional thinking of consumers; I'm not literally saying "you just got the best" b/c the 8gb version is any greater than the 4gb version. That's a different discussion).
(3) Gaming Satisfaction - As demonstrated here, there is some debate about the current value of 4gb vs 8gb vram. Independent of who is right, it demonstrates that some consumers will view the extra 4gb as an actual benefit to their gaming enjoyment.
In this instance, the "perceived value" to many buyers will be substantially greater than a mere $30 (15%, or "hmmm, I can get 4gb more for a bit more than my sales tax....not bad"). The "perceived value" of 4gb to many is actually quite high in this case (& remember "perceived value" is not the same as "actual value" - that's the whole purpose of decoy pricing). And, as it not uncommon in pricing schemes, the perceived value is mostly emotional (some will argue differently), but substantial in this case.
In a nutshell, AMD has posed the following question to consumers by positioning the 4gb card vs the 8gb cards with only a $30 price different: Is foregoing the increased gaming satisfaction you'll receive having 8gb VRAM, the future-proofing of 8gb you obtain, and the sense of purchasing the "best of the best" of your tier really worth sacrificing but for a measly $30? Really? You sure? You're dropping $200? Come on, it's just $30 more. You can make sure you don't waste your entire investment of $200 for just $30 more? (future-proofing concern). Sale.....cha ching.
Ultimately, while $30 more on a $200 card isn't much to consumers, it will result in a significant amount of margin/revenue/profit to AMD on a sale that they were already going to make. This is precisely the purpose of decoy pricing.
At bottom, the 4gb/8gb pricing disparity allows AMD to capture additional profit and revenue without threatening sales or market position of the products. It provides perception value for many consumers (via future proofing, belief that it may provide better gameplay, etc), confirms marketing equilibrium for AMD (enabling AMD to market 8gb cards as its competitor has), and is great for competition as it will strengthen AMD's bottom line (& I think few would disagree that at this juncture, the market for CPU's & GPU's only benefits from AMD being a financially viable entity). It's a win/win all around.
There's a lot more to say on the topic. For, e.g., there are other reasons for an 8gb independent of pricing structure, "necessity" or "gameplay improvements", such as market perception. After all, AMD wants to be able to sell an 8gb product b/c it's competitor does, and if AMD didn't the market could perceive that its products are inferior or automatically targeted at budget people that don't care about performance. They could have satisfied the market perception need by selling the 8gb for substantially higher than $30 more. Alas, they didn't. And, I'm confident my explanation above is precisely why (and they get the added benefit of positive market perception "wow, an 8gb video card for only $230....great price").