AMD Ryzen 5 7640U's Advantages
Integrated graphics card
Higher specification of memory (LPDDR5x-7500 vs DDR5-5600)
Higher base frequency (3.5GHz vs 3.2GHz)
Lower TDP (15W vs 28W)
AMD Ryzen 5 PRO 8540U's Advantages
Released 11 months late
Newer PCIe version (4 vs 4.0)