Gigabit internet without gigabit speed

I recently moved to a new apartment and transferred my service to that apartment. At my prior location, I would run a speed test and get on average 950Mbps on multiple speed tests on the internet, including Xfinity's.

Since moving, my speed now averages at around 650Mbps. I am connected in the same way both times. Does the new apartment just not have the infrastructure for gigabit speeds? I'm unsure what exactly could be causing this difference.