new 5K iMac GPU question

I am contemplating moving up to a new 5K iMac, but really it comes down to how much of an improvement I will see in Indesign and Illustrator. I do 99% of my work in Indesign and a lot of the placed files are complex vector .ai and .eps files. My current 5K iMac handles it ok, but it can start to slow down as things get more complex

I currently have the AMD Radeon R9 M295X 4096 MB in my 5K iMac. Now I am wondering if Adobe utilizes the new GPU's in the new just released iMacs. Will I see a huge performance improvement with:

• Radeon Pro 575 with 4GB video memory
• Radeon Pro 580 with 8GB video memory

I would go with the Radeon 580 as it is only a few hundred more when pricing out the machine, but will Indesign and Illustrator use the new GPU's for large noticeable improvements?