There's no claim of any 5-6x faster than previous there. It says "fastest integrated" (and in the fine print that integrated is specifically unified monolithic die, eliminating chiplet-style products), and then also "M1 delivers significantly higher graphics performance than the very latest PC laptop chip — for up to 2x the graphics speed."

So take the 4800U, which has among the fastest commercially available integrated graphics in a monolithic die, and double the GPU performance. If you needed a discreet GPU in your laptop previously this probably won't change that.