Have a Sapphire HD7970 Vapor-X GHz Edition(3GB, HYNIX AFR memory)
Stock bios was giving ~52sol/s (1050/1500)
Tried GIGABYTE 7970 with HYNIX AFR Memory, OS started but mining failed(0.0 sol/s)
After that flashed ASUS R9 280X with HYNIX AFR memory.
And now my GPU gives ~83-87sol/s, peaking at 96sol/s in Claymore's v4.0

Got a little excited seeing 90 sols on 280x, flashed gigabyte elpida to sapphire elpida, bricked the card. good thing there are 2 bios'es in this card. Restored the primary using the backup.
Anyone with sapphire elpida bios with improve hashrate? Im getting 65 at the most. Thanks.
Thanks very much adaseb.
Guys stop flashing the wrong firmware bios. Wait until someone with those cards mods the BIOS. Really surprising its actually hashing for you since its a completely different manufacteur even.
Either way its nice to see these old GPUs back in the game, they were almost forgotten with the RX series but are now killing 470s and 480s left and right.