One of the most used functions in Photoshop is the new file function and with Photoshop CC 2017.1.1 it's painfully slow. When I use Photoshop CC 2015 opening a new file is quick.
I see the following screen pops up in Photoshop CC 2017
This new version of Photoshop requires me to wait up to 30 seconds before I see this New Document screen. Needless to say this makes Photoshop CC 2017.1.1 unusable in its current form.
My system specification are
You could try setting you preferences to use the old new document interface to see if that is any better. You should also use menu Help>System Info and copy and past all the information here. Perhaps some mac user will see something that might be a problem in you configuration. Check on Apple site make sure you have the latest display device driver
install for your model mac.
Selecting the "Use Legacy "New Document" Interface correct the issue.