It could make sense to reduce the clock speed from 5800X to 5700X for better efficiency and lower heat output.
It could make sense to reduce the clock speed from 5800X to 5700X for better efficiency and lower heat output.
The gap between 5700x and 5800x is similar to a 10-20 watt drop in power use. Your CPU doesn’t run at full 100 watts constantly; it adjusts based on workload, so when idle it uses roughly the same amount as when running at 5800x. This can save you a few kWh each month, which translates to just a couple of dollars or euros saved.
Let it operate up to 90°C, the CPU can run for decades at full capacity without problems. Using all available temperature headroom is key; just avoid voltages above around 1.4V or you may encounter voltage rollover, possibly dropping below 90°C.
I didn't grasp the beginning of your message. Choosing the 65W Eco Mode is exactly what I've been doing... The last time I updated the BIOS was just before installing the 5800X. My motherboard has stored the XMP profile I set for my RAM, but it doesn't appear to maintain the 65W Eco Mode consistently.
This seems like an unusual problem with your motherboard. It's unclear what else to say since nothing should alter your BIOS configuration. As everyone has mentioned, avoid swapping it out—since the 5800X uses higher-grade silicon, downgrading doesn't make sense while you're experiencing issues. Your BIOS settings should stay as they are; I'm not sure. Be sure to back up your BIOS, and some motherboards let you save the eco mode into the default settings. Experiment a bit to see what works.