If you accidentally bought two AMD Epyc 7551P CPUs for a dual-socket motherboard like the H11DSI-NT, it's important to note that the 'P' variant is not intended for use in a dual-socket configuration. Placing both 'P' CPUs in the motherboard could potentially lead to compatibility issues or system instability.
The 'P' CPUs are designed for single-socket setups, and using them in a dual-socket configuration might not work as intended. It is not recommended to try using both 'P' CPUs in the motherboard simultaneously, as it could potentially cause damage or result in a non-functional system.
For your particular predicament, the best course of action would be to contact the vendor or store where you purchased the CPUs and explain the situation. They might be able to help you with an exchange or return, especially if it's a genuine mistake. If an exchange or return is not possible, you might consider selling the 'P' CPUs and purchasing compatible dual-socket Epyc CPUs.
Overall, it's crucial to ensure that the components you use in your system are compatible and correctly configured to avoid any potential issues or damage to your hardware.
PC Hardware Specialist