She and Furber co-designed the ARM processor powering Acorn's computers during the 1990s and virtually every mobile phone and tablet in the world nowadays – 300 billion sales of ARM powered chips to date (Jan 2024). She co-designed the ARM3, ARM610 and ARM 700 processors and ARM7500FE single chip computer. She created Acorn Replay multimedia software.

By 1999, Sophie developed the Firepath SIMD LIW processor and she and six others founded Element 14 to exploit this for ADSL. Sophie led the design of the instruction set for Firepath, wrote the Architecture Guide and led the SoC designs. Broadcom bought Element 14 at the end of 2000 and went on to win the majority of the Central Office DSL business. Sophie continues to develop the Firepath processor.

Sophie is a Broadcom Fellow and Distinguished Engineer, a Fellow of the Royal Society, a Fellow of the Royal Academy of Engineering, a Distinguished Fellow of the British Computer Society, a Fellow of the Women’s Engineering Society, an honorary Fellow of Selwyn College, Cambridge, an honorary Fellow of the Institution of Engineering and Technology (IET) and an honorary Fellow of the Institution of Engineering Designers (HonFIED). She has an honorary doctorate of science from Cambridge University and a CBE.