GlobalFoundries is claiming they are making 5GHz operating devices. How else do you expect performance to increase when you shrink down the process? Faster moving transistors! How do you make them operate faster? Design them to function faster! What do we know? GlobalFoundries said they are making 5GHz operating Server, Data Center, ASICS parts! GlobalFoundries have made massive beneficial changes to the design of their transistors! It's not rocket science it's deductive reasoning based on the information provided.
Here is the claim of 5GHz operating devices:
Here is the transistor performance at 7nm compared to 14nm
Here is what the transistor looks like at 14nm vs. what they look like at 7nm. Notice the drastic change in shape of the transistors!
We know that a long rectangular slightly rounded edges provides the best characteristics for high performance transistors! GlobalFoundries 14nm transistors look to be closer to the 22-nm on the chart below, while the 7nm looks closer to the 10nm. While being a much more refined smooth design as well.
Here is Intel's 10nm transistor design. It's looks really similar to GlobalFoundries 7nm.
Here are the details of different cells or IP blocks that can be implemented of which include 7nm HPC. It's as simple as saying okay build on this IP foundation for my 7nm chips and they select 9T libraries for the process: