TechPowerUp reports Sapphire screwed up the BIOS of some Sapphire Radeon HD 5770 Vapor-X cards, the issue disabled 10 percent of the 800 stream processors of this video card.
Statement from Sapphire: "SAPPHIRE Technology has determined that a small batch of the recently launched HD 5770 Vapor-X graphics cards was shipped with a BIOS that enables only 720 stream processors instead of the full 800 stream processors available on this model. Other performance parameters are to the correct specifications. This issue can be rectified with a BIOS update. The correct BIOS code can be downloaded from sapphiretech.com and some partner websites. We regret any inconvenience caused to end users."