Summit boasts a peak performance of 200,000 trillion calculations per second and will be eight times more powerful than America's current top-ranked system, Titan. It took four years to build, according to Rometty.
For researchers, "an experiment that might have taken 27 years to 13,000 years, they can do in a day," she said. "You will have new compounds, new cures for cancer."
Energy Secretary Rick Perry said the machine should have a profound effect not only on health care but on energy research and cybersecurity.
"This is nothing less than world-changing," Perry told "Power Lunch."
The U.S., which was in fifth place in terms of the world's fastest computers, will now move back up to the No. 1 spot, Perry said. But he expects China, which before Summit had the two fastest computers in the world, will work hard to reclaim the top spot.
"This competition is real. It's not going away," Perry said.
For Nvidia CEO Jensen Huang, Summit is just the beginning of "exciting" growth ahead.
"The architecture for Summit is going to be the way computers are built in the future. It's a multibillion-dollar industry," he told "Power Lunch."