SmartShift was introduced with the Renoir mobile APUs, it's a power balancing technology for the CPU and GPU. Basically, it can dynamically assign TDP budget not used by the CPU to the GPU and vice versa. The feature works on a platform level and requires not only an AMD APU and AMD discrete GPU, but also some specific cooling layout decisions.
It's a brand new technology and to @dell credit they jumped on it first. I explained reasons why during my interview with @pcworld @Gordonung @BradChacos No more SmartShift laptops are coming this year but the team is working hard on having more options ASAP for 2021.— Frank Azor (@AzorFrank) June 4, 2020