Fractile raises $720M Series C to build AI chips with stacked DRAM

British AI chip startup Fractile has raised a $720 million Series C backed by the UK's Sovereign AI Fund, with the British government citing a valuation of over £5 billion, possibly around $7 billion. The round was led by Thrive Capital, Founders Fund, Lightspeed Venture Partners and Redpoint. Fractile pairs its chips with a machine learning compiler and, after a pivot, stacks DRAM on top of each chip to try to bypass the usual memory-versus-capacity trade-off, which the company sees as increasingly costly for agentic AI. CEO Walter Goodwin said the funding will let the startup ship its first chips and systems next year.