The headline is quite misleading to folks with software backgrounds: "Clocked at 427 GHz" implies that the paper's authors measured something with a signal at

The headline is quite misleading to folks with software backgrounds: "Clocked at 427 GHz" implies that the paper's authors measured something with a signal at 427 GHz. In truth, the authors measured up to 30 GHz and extrapolated a figure-of-merit f_T to be 427 GHz. For comparison: InP-based HBTs were measured north of 400 GHz back in the 90s, which tells you that Graphene in this paper is behind where InP was 20 years ago. Of course, that doesn't make for sexy headlines. If you're interest in what the figure-of-merit means: f_T is the theoretical maximum frequency that you can build an amplifier and still have the transistor provide gain. Practicalities limit amplifier design (or digital circuits) to frequencies much lower than f_T.