NVIDIA's 2014 medium-high-range graphics card the GeForce GTX 970 was and is a powerful board - I'm using one right now, and it's perfectly capable of running games at decent settings at 3440x1440 - but there was one fly in its otherwise well-received ointment. Though billed as having 4GB of onboard memory, the reality was that its RAM was divided into one 3.5GB chunk and one slower 512MB chunk. NVIDIA refutes that this meant the board was in effect just 3.5GB, and claims performance was not meaningfully impacted. However, the firm was also accused of overstating specs regarding the 970's render output processors and L2 cache.
Numbers, numbers, but what you really need to know is that the alleged misrepresentation led to a clutch of class-action lawsuits - which NVIDIA has now agreed to settle. By refunding every American 970 purchaser 30 bucks.
AFAIK this offer is not available to folk outside the US, as the class action lawsuits (16 of 'em!) were filed in California. Perhaps the settlement could lead to things happening elsewhere, but it's important to note that one of the terms of the deal is that NVIDIA does not have to admit to any wrongdoing, and can continue to deny that it is guilty of false advertising, deceptive business practice and similar charges filed in the lawsuit.
Of course, this is a settlement - and an expensive one at that - in order to avoid a full trial. Whether done for expediency's sake or a sense that the winds would blow against NVIDIA, we cannot know. What we do know is that there will be $30 available to any US GTX 970 purchaser who files a verifiable claim, and that NVIDIA will also stump up $1.3 million in legal fees. There is apparently no upper limit on how many of the $30 claims it will honour, other than the number of Americans who purchased a 970.
As for the specs in question, as well as that 3.5GB/4GB issue, the 970 was advertised as having 64 render output processors when in fact it had 56, and 2,048KB of L2 cache rather than the 1,792KB reality. The $30 figure, just south of 10% of the card's $350 list price, is supposed to reflect the discrepancy in performance between the advertised specs and the real ones.
Though agreed upon by both sides of the argument, the settlement is provisional for now. As such, no, you can't go make your claim just yet, but hopefully soon.
Via The Register, which also hosts a PDF of the full settlement agreement.