I upgraded from a Ryzen 5 3600 to a Ryzen 7 5800X3D in an ASUS TUF Gaming B550-PLUS system running Windows 11. At idle, the CPU shows only about 1–3% usage, but package power stays around 30–35W and temperatures sit at roughly 65–70°C. The 3600 was noticeably cooler under similar conditions.
I have already reapplied the thermal paste, reseated the cooler, checked the mounting and fan operation, tried different PBO and voltage settings, reviewed Windows power options, confirmed that the AMD Ryzen Balanced plan is enabled, checked background processes and C-state behavior, and updated the BIOS for the 5800X3D. The system uses a 240 mm DeepCool liquid cooler with two fans that has worked reliably for about six years.
Could this be related to BIOS or AGESA behavior, chipset drivers, C-states, SOC voltage, or another power-management setting? Is 30–35W at idle unusually high for this processor, and what would you check next?
4 Answers
A negative PBO curve offset can help substantially. One user reported that a -20 Curve Optimizer setting reduced temperatures while allowing an all-core clock around 4.45 GHz. Results vary by chip, so test stability carefully rather than copying a voltage or curve value blindly.
A 240 mm radiator should normally be adequate, but cooler performance, pump speed, mounting pressure, fan curves, and radiator condition still matter. Another 5800X3D owner on the same motherboard reported roughly 40–45°C at idle and 70–75°C under sustained load with a dual-tower air cooler, so 65–70°C at idle suggests either unusually high idle power or a cooling/contact issue rather than simply the CPU being warm by design.
The 5800X3D’s cache layer acts like insulation between the silicon and cooler, so a larger radiator does not always reduce temperatures dramatically. However, that mostly explains higher temperatures under a given power level; it does not fully explain unusually high idle power. Check the actual CPU core voltage and SOC voltage with a monitoring tool, verify chipset drivers and BIOS settings, and make sure no background device or software is preventing package C-states from being used.
The 5800X3D generally runs warmer than a 3600. It has two more cores, higher performance, and the stacked 3D V-Cache sits between the cores and the heat spreader, making heat harder to transfer. That means the same cooler can produce higher temperatures even when the CPU is not heavily loaded. Still, 30–35W at idle is on the high side, so checking SOC voltage, load-line calibration, and whether the cores are actually reaching deep sleep states would be worthwhile.
I have already tried several PBO and voltage adjustments, but the idle package power remains around 30–35W. I will compare the readings with different Curve Optimizer values and monitor whether the cores are entering their deepest sleep states.