While the AMD Ryzen 4000 series of CPUs are highly regarded for their impressive performance and efficiency, they are not without their faults. Here is a list of some of the bad things about the Ryzen 4000 series CPUs:

1. Limited availability: Due to high demand, the Ryzen 4000 series CPUs can be difficult to find in stock. This can make it challenging for users who are looking to purchase a new laptop or notebook.
2. Limited upgradability: As the Ryzen 4000 series CPUs are designed for laptops and notebooks, they cannot be easily upgraded. Users who want to upgrade their CPU will have to purchase a new laptop or notebook.
3. Higher power consumption: The Ryzen 4000 series CPUs have a higher power consumption compared to previous generations of mobile CPUs. This can result in shorter battery life for laptops and notebooks.
4. Higher cost: While the Ryzen 4000 series CPUs offer excellent value for money compared to other CPUs in their class, they are still more expensive than previous generations of mobile CPUs.
5. Limited compatibility with older devices: Some older devices may not be compatible with the Ryzen 4000 series CPUs, which can make it challenging for users to upgrade their devices.

In conclusion, while the AMD Ryzen 4000 series of CPUs offer excellent performance and efficiency, they are not without their faults. Users should consider these issues when deciding whether or not to purchase a Ryzen 4000 series CPU.