Many users have discovered that you can unlock the extra 4Gb VRAM on 4GB AMD Radeon RX 480 GPUs by simply flashing it with the BIOS. It seems like some 4GB versions of Graphics card contain the same chips as 8GB Radeon RX 480 cards, yet have 4GB of RAM disabled in the BIOS. This ought to make it conceivable to flash the firmware of the more costly 8GB Radeon RX480 to the less expensive 4GB version.
AMD Radeon RX 480 4GB can be flashed to more expensive 8GB model
A Dutch user on the site Tweakers discovered when he analyzed his Powercolor 480 4GB graphics card. He found that his card contained 8 memory chips from Samsung, each with a limit of 8Gbit. Altogether the card had 64 Gbit or 8GB of RAM, while it’s sold as a 4GB model. Additionally, the PC recognizes the card as a 4GB model, the other 4GB was crippled in the BIOS.
It should indeed be possible to flash a 4GB card to an 8GB card, if the right equipment is available. In a Reddit AMA (Ask Me Anything) an AMD representative has expressed that,
“In the market, you will see a version with 8GB of physical memory, and a version of 4GB of physical memory. We sent reviewers an 8GB model with a BIOS that allows them to flash between 4GB and 8GB available memory so they could perform testing on both hardware configurations.”
Users that might want to get their hands on this tool are stuck between a rock and a hard place, it’s not accessible to any other individual other than a few reviewers (at the moment).
Flashing the card is justified regardless of the cash, the 4GB card is sold at $199 while the 8GB version has an MSRP of $239.