Hello
@PeterAF,
Welcome to the forum and glad to hear the build went well. Sleep issues are most commonly caused by misbehaving USB devices, typically those connected internally, such as:
- Liquid all-in-one coolers (with USB connection)
- RGB lighting controllers (with USB connection)
- Smart power supplies (with USB connection)
- Bluetooth (USB data cable)
We always go through the Process of Elimination to identify the culprit. This is easily done by disconnecting all internal USB connections and then connecting only one of them at a time.