Graphics Card Suggestion for Mac Pro Mid-2012

Mac Pro Mid-2012 3.2 GHz Quad-Core Intel Xeon tower with 32 GB 1066 MHz DDR3, and the original ATI Radeon HD 5770 1024 MB Graphic Card. It's running pretty well, except that the graphics card is long overdue to be replaced. 

Currently I'm on CP Version 11, OS 10.12.6 , and I cannot do upgrade anything until I replace the graphics card. 

What card will support the new CP?

Thanks!