AMD produces the chip (GPU Core) and sells them to 3rd parties (MSI, Sapphire, Gigabyte, ASUS, XFX & More) to produce cards with. AMD produces very few complete cards.
the difference between the same card (e.g. 7770) from different manufactures tend to only be very slight differences.
The card you’re looking at is an AMD 7770 GPU on a card produced by MSI.
MSI is given the AMD 7770 GPU but will choose their own VRAM modules, Capacitors, VRM's, PCB & ETC to use to create the complete card.