Basically the Biostar  RX 470D is using a cut-down chip. A Radeon RX 470 should have 2048 shader processors, this one only has 1792. The memory frequency has been increased from 6000 MHz to 7000 MHz though. 

The clock speed of the GPU is 1200 MHz. This is aimed at the mining market even though the GPU has display ports. This could mean that AMD is playing safe and not removing the display ports. 

The Biostar RX 470D features a heatsink cooler with 2 fans and comes in a red and black design. The D series GPUs could all be aimed at the mining market. Miners are causing GPU shortages around the world and this is becoming rather annoying for the average consumer that is not looking to get into cryptocurrency mining.