Announced today, the new 2019 Mac Pro looks like an updated "cheese grater" Mac Pro. Featuring a massive spec bump over the current Mac Pro, the new desktop features 8 PCIe slots and Apple's new Mac Pro Expansion (MPX) Module system. MPX Modules use a proprietary connection that allows for enough PCIe lanes to deliver 500 Watts and support dual Radeon Pro Vega Duo GPUs with a total of 56.8 teraflops of computing power and 128 GB of HBM2 VRAM.
https://www.notebookcheck.net/Return-of-the-Cheese-Grater-Apple-announces-new-Mac-Pro-desktop.422993.0.html