Radeon Pro 5700 xt vs Radeon Pro 5700

Hello, I'm about to buy the 2020 iMac 27 inch, 3.8GHZ intel core i7 processor, 8GB RAM (will upgrade to 64GB), and wanted to know if there is much difference with graphics cards Radeon Pro 5700 xt vs Radeon Pro 5700 when it comes to rendering and exporting in Premiere? 

There seems to be a big jump in quality from the base model to the 5700 xt but not so much to the 5700. 

Would appreciate some input.

Thanks!