Question Dual GPU 6800 XT + 7900 XTX

[mrmaruniversal]

For testing purposes, i decided to to take my 6800 XT from a PC I use as a steam console and throw it into my main PC. As I know most games do not support crossfire and I do not intend on using dual gpu's for gaming but rather different tasks and balanced work loads. Does having a 6800 XT with a 7900 XTX hurt performance in anyway? (Running games on XTX, rendering on XT) Its a silly question, just curious if its too much data being sent around the board that could hurt performance. I currently have my monitors connected to the XT (because XTX idles at 100W) and selecting games to render on the XTX. (Gaming in 1440p and 4k)