I am also an owner of the R9 280 OC Rev 2. Specifically, the GV-R928XOC-3GD Rev2. This card comes with the F70 BIOS on it. For those unaware, GPUZ will see this BIOS as version 015.041.000.000.000000. The Gigabyte website offers no update for users running the R9 280X with Hynix memory, and the F70 BIOS. Mine is this version with Hynix memory on it, as it will be for anyone who's card also has the F70 BIOS. I do have some good news for people though on how to get this particular card working without artifacts. Note, this will not work with cards which have Elpida memory on them. This is only for the GV-R928XOC-3GD Hynix Rev2 model. Out of the box, my card was also artifacting, as is the case for many people. As many people know, the R9 280X is actually an HD 7970 Ghz edition. In this case, the GV-R928XOC-3GD is actually the exact same card as the Gigabyte GV-R797TO-3GD. This is the Gigabyte HD 7970 Ghz edition. The good news is, this card is the exact same, and uses the exact same Hynix memory. You can use the BIOS from this particular HD 7970 Ghz edition card, and the artifacting will stop. It has the F62 BIOS on it, and this BIOS is 100 percent compatible with the GV-R928XOC-3GD Hynix Rev2 model. GPUZ will read the BIOS as 015.026.000.000.000000. This BIOS has a couple differences. First off, the F62 BIOS runs 1050 MHz at 1.2 volts, and when boosting up to 1100 MHz, it runs at 1.256 volts. This is an increase from the 1050 MHz at 1.163 volts, and 1100 MHz at 1.2 volts of the F70 BIOS. The F62 BIOS also stops all of the flickering within the desktop environment as well. I have been a computer tech for 11 years. I put the BIOS on my card, as well as a customer's card a couple days ago, and neither of us have any issues anymore.
As always, make sure you know what you are doing. I am not responsible if you do this incorrectly. Also, be aware that because you will be flashing to a HD 7970 Ghz edition BIOS, your video card will now be seen as such in windows. This really should not matter to anyone since the R9 280X and HD 7970 Ghz edition are the same card. I have uploaded the BIOS for people. If you don't know how to flash your card, do an internet search and learn. In DOS you will run the following command
atiflash -f -p 0 biosfilename
This will allow a force flashing of the card. You will no longer have artifacting once you flash to this BIOS.