Mod note: Run those files at your own risk!
This works for the R9 models tp The R9 models X, They are almost identical boards just with a few less shaders and such, My mate done this for me and it gave me an extra 50 - 75 KH/s. I have a 290x Now
Turning your R9 270 to a R9 270X
1) Download Latest 270x Bios (https://www.dropbox.com/s/ghgmpiota1jrwpr/ATI.R9270X.2048.130816.rom)
2) Download atiflash (http://sgminerconfig.com/atiflash.zip)
3) Extract atiflash to a known location
4) Go to command prompt and run 'atiflash.exe -f -p 0 ATI.R9270X.2048.130816.rom', This will take a little while
5) Reboot and your all good to go.
Turning your R9 280 to a R9 280X
1) Download Latest 280x Bios (https://www.dropbox.com/s/ntj1qu1fpw99sj5/Asus.R9280X.3072.130828_1.rom)
2) Download atiflash (http://sgminerconfig.com/atiflash.zip)
3) Extract atiflash to a known location
4) Go to command prompt and run 'atiflash.exe -f -p 0 Asus.R9280X.3072.130828_1.rom', This will take a little while
5) Reboot and your all good to go.
Turning your R9 290 to a R9 290X
1) Download Latest 290x Bios (https://www.dropbox.com/s/gzq7repk1l5ielh/ATI.R9290X.4096.131003_1.rom)
2) Download atiflash (http://sgminerconfig.com/atiflash.zip)
3) Extract atiflash to a known location
4) Go to command prompt and run 'atiflash.exe -f -p 0 ATI.R9290X.4096.131003_1.rom', This will take a little while
5) Reboot and your all good to go.
P.S. if you dont trust my links you can download ATIFlash and roms from lots of places. I just thought it would be convenient to the thread.