AMD's Smart Memory Access was recently announced. In unoptimized games, they're projecting a 5% performance boost between their stock overclock and SMA (rumors put the overclock at only around 1%).
The bigger issue here is bandwidth. AMD hasn't increased their APU graphics much because the slow DDR4 128-bit bus isn't sufficient (let alone when the CPU and GPU are both needing to use that bandwidth).
I also didn't mention PCIe lanes. They are notoriously power hungry and that higher TDP chip not only has way more, but also has PCIe 4 lanes which have twice the bandwidth and a big increase in power consumption (why they stuck with PCIe 3 on mobile).
It's also notable that even equal cache sizes are not created equal. Lowering the latency requires more sophisticated designs which also use more power.
The bigger issue here is bandwidth. AMD hasn't increased their APU graphics much because the slow DDR4 128-bit bus isn't sufficient (let alone when the CPU and GPU are both needing to use that bandwidth).
I also didn't mention PCIe lanes. They are notoriously power hungry and that higher TDP chip not only has way more, but also has PCIe 4 lanes which have twice the bandwidth and a big increase in power consumption (why they stuck with PCIe 3 on mobile).
It's also notable that even equal cache sizes are not created equal. Lowering the latency requires more sophisticated designs which also use more power.
https://www.amd.com/en/technologies/smart-access-memory