Find the appropriate location for the AIO on the MSI B450 Tomahawk Max.
Find the appropriate location for the AIO on the MSI B450 Tomahawk Max.
It doesn't really matter to plug it into an SYS_FAN header. AIO headers are just standard fan connectors with possibly thicker copper traces on the board, helping deliver more current to the pump in the cooler. Most motherboard fan headers already work well, so a special header isn't necessary. I'd skip the CPU_FAN header for the pump since it usually monitors bios and tries to tweak voltage or speed, which could disrupt the pump's performance. The pump in your AIO should handle normal voltage changes fine.
Your PC won't start because the CPU header isn't recognized, even though you're plugging in the power. This issue can prevent the system from booting properly.
It should power on but emit a beep or display a warning about the fan not being detected. Press F1 to proceed and see the message. Likely some motherboards can start without a fan, though this is rare. It’s normal for certain boards to take longer to boot after first use with a specific processor—sometimes up to 1-2 minutes without any visual feedback. BIOSes may include microcode updates that need to be applied directly to the CPU if it’s running an outdated version. They often run multiple uploads and resets to ensure compatibility, checking new RAM modules and testing their timing against built-in settings or XMP/DOCP profiles. This process can add extra time. Don’t worry if it takes a minute or two; unplugging too early won’t harm the system but may prolong the start-up.