Tom's Hardware Guide published a review on Sapphire Radeon RX Vega 64 Nitro+
A quote from the article:
Sapphire's engineers took their sweet time creating a graphics card that heats up the third-party Vega 64 market by staying cooler than the competition. We run its Radeon RX Vega 64 Nitro+ through our test suite.Sapphire Radeon RX Vega 64 Nitro+ Review @ Toms Hardware
Sapphire took its time getting a home-grown Radeon RX Vega card to market, and that's not a bad thing. While some competitors sneakily seeded production validation test boards (the ones that precede mass production), Sapphire kept to itself and made sure the Radeon RX Vega 64 Nitro+ was running well. When you think back to the issues those leaked cards demonstrated, Sapphire did well to keep its efforts quiet until the right time.