Folks willing to try their luck have long had success "unlocking" the full-fat forms of certain AMD chips. The Phenom II X3 720 is perhaps the most recent example. Some builders were able to turn on that chip's ostensibly-disabled fourth core with the right motherboard and firmware, although the long-term stability and reliability of that fourth core was an open question.
The Polaris 11 die
Now, reports are coming in that it's possible to enable an extra two GCN compute units on certain Radeon RX 460 graphics cards with a community-produced firmware update. That firmware enables all 1024 shaders and 64 texturing units on Polaris 11 chips. The GPU wizards at TechPowerUp say that prospective unlockers will need a Sapphire Nitro RX 460 4GB card or an Asus Strix RX 460-O4G card to start with, plus the proper modified firmware to flash for each card from overclocking.guide.
The Sapphire Nitro RX 460 4GB card
Before we go any further, it's worth noting that Sapphire's Nitro RX 460 doesn't have the dual-BIOS switch common on many Radeons, so a failed firmware update could brick the card. We can't comment on the Asus Strix RX 460's setup. This unlocking process could also enable malfunctioning hardware or cause other weirdness. Proceed at your own risk. So long as one is willing to clear those hurdles, though, TechPowerUp reports that an "unlocked" Sapphire RX 460 enjoys about a five-percent performance bump in The Witcher 3, while the Asus Strix RX 460 gets about a 10% boost. Not bad.
All that said, the unlocking party may not be long-lived. TechPowerUp also reports that AMD has resumed firmware signature checking on its cards with the Radeon Software Crimson ReLive Edition update, so that driver will fail to load with cards running unsigned firmwares. Folks trying to flash their cards will have to stick with older drivers—not an appealing prospect considering ReLive's many benefits. Still, if a smidge of extra performance is worth the inconvenience, the brave can at least give it a shot on compatible cards.