While some previous graphics cards had an ability to unlock extra shaders, now it appears that some RX 480 4GB graphics cards can be unlocked to 8GB versions, with a simple BIOS flash.
Apparently, some of the early 4GB versions of the RX 480 actually come with 8GB of memory, but have been flashed with BIOS that prevents the GPU from addressing more than 4GB of memory.
According to a report from Techpowerup.com, unlockable RX 480 4GB versions physically come with 8GB of memory and it should be quite easy to check what type of chips are on the card before flashing.
This was originally discovered by Tweakers.net and on the Powercolor 480 4GB graphics card so this is not an AMD sample but rather a retail card.
Both 4GB and 8GB version have the same amount of chips but 4GB versions uses 4Gbit chips while 8GB uses 8Gbit chips.
AMD already confirmed that it sent out an 8GB model to reviews with two BIOS versions which allow them to flash between 4GB and 8GB of memory.
These unlockable graphics cards are probably a very limited and early batch so it is practically a lottery if you end up with one.
Source:
Techpowerup.com.