The graphics processing unit does nothing to help the processing power of your computer.
Etabs recommends minimum 8gb of ram for proper operation. My computer has 16gb of ram and I would argue it could do with more. Because for example, I have no design programs running at the moment, just office programs, i.e. word, excel, outlook. and this browser window, and I'm currently using 8gb. So that's half of my ram in use, without etabs even being open.
So that lack of RAM isn't helping the solving speed, but it's also a complex analysis for a building that tall and inherently will be a long time running.
How long does it take for the model to run?