Graphics card ROM backup for an XFX Radeon HD 7870, the suffix bak marking it as a saved original. The RAR is 39.7 KB, consistent with a single VGA BIOS image. Such a file is used to restore a card after a failed or unsuitable BIOS flash, using ATIFlash or an external programmer on the card's EEPROM. Make sure the card model and memory configuration match, and dump the current ROM before writing so you can roll back if needed.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @biosarchive. Enginerys does not host this file.
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.
Back up your own chip before writing any dump, and match the full board number and revision. Flashing guide →