Tom's Hardware Guide published a review on Radeon R7 250X: Reprising Radeon HD 7770 At $100
A quote from the article:
AMD's name might be new, but we're already intimately familiar with its Radeon R7 250X (formerly known as the Radeon HD 7770). Can AMD take an old piece of hardware and turn it into something you want to spend money on in 2014? Let's have a quick look...Radeon R7 250X Review: Reprising Radeon HD 7770 At $100 @ Toms Hardware
Except for the Radeon R9 290-series cards, sporting AMD's Hawaii GPU, all of the other Radeon R7 and R9 boards we've seen are re-branded versions of the Radeon HD 7000 family. The Radeon R9 280X falls between the Radeon HD 7970 and 7970 GHz Edition. The Radeon R7 270 and 270X are based on the Pitcairn GPU. The Radeon R7 260X hosts the same graphics processor as the Radeon HD 7790.
Clearly, the company feels that the first-generation GCN graphics cards still have a lot to offer, especially with a handful of clock rate tweaks. We wouldn't necessarily disagree; the Radeon line-up offers a viable spectrum of performance, from the entry-level Radeon R7 240 to the flagship Radeon R9 290X.