This would mean the quantum system is 1.5 to 2 billion times faster than a classical supercomputer for this problem. We do not know details of the problem and other researchers have to confirm the work.
This is only one problem or on class of problem and does not mean all problems. The IBM Summit has about 200 petaflops of performance. These kinds of claims need a lot of verification because other mathematicians and researchers could optimize the algorithm or performance of a regular computer to solve it faster than what the original researchers believed. The paper apparently was only available briefly.
Google Researchers are thus talking about Quantum Supremacy. This would be when quantum computers solve problems faster than classical or solve tasks beyond the capabilities of classical computers.
In 2013, D-Wave Systems thought they could solve a problem 3600 times faster than regular computers. But other researchers determined that there were better algorithms and programs.