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 remain between 65 and 70°C. My previous Ryzen 5 3600 was considerably cooler under similar conditions. I have already reapplied thermal paste, reseated the cooler, checked the mounting and fan operation, tested different PBO and voltage settings, reviewed Windows power settings, confirmed the Ryzen Balanced plan is enabled, checked background processes and C-state behavior, and updated or configured the BIOS for the 5800X3D. The CPU is cooled by a 240mm DeepCool liquid cooler that has worked reliably for several years. Could this still 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 should I investigate next?
4 Answers
The 5800X3D naturally runs warmer than a Ryzen 5 3600. It has two more cores, higher performance, and 3D V-Cache positioned between the cores and the heat spreader, so heat does not transfer out as easily. That means the same cooler can produce noticeably higher temperatures even when the CPU is not heavily loaded. However, 30–35W at true idle is on the high side, so checking SOC voltage, load-line calibration, and whether the cores are actually entering deep sleep states would still be worthwhile.
A 240mm radiator should generally be enough for this chip, but its age, pump speed, mounting pressure, and fan or pump curves are worth checking. A comparable 5800X3D system can idle around 40–45°C and reach roughly 70–75°C under sustained gaming or all-core load, although temperatures vary with room temperature and case airflow. If the pump is slowing down or the cold plate is not making good contact, even modest package power can result in high temperatures.
The cache layer makes the 5800X3D harder to cool than its power rating might suggest. In other words, a high temperature at only 30–35W does not automatically mean the cooler is defective. Still, compare package power with individual core sleep states using tools such as Ryzen Master or HWiNFO, and check whether another program is periodically preventing idle. If the CPU never reaches low-power states, BIOS settings, chipset drivers, or a background utility may be responsible.
A negative PBO curve can help. One user reported that a -20 curve offset reduced temperatures substantially while allowing the processor to maintain about 4.45 GHz all-core. Curve Optimizer results vary from chip to chip, though, so test stability carefully rather than copying an aggressive value blindly.
The cooler is a 240mm DeepCool unit with two fans, and it has been running without obvious problems for about six years. It cooled the Ryzen 5 3600 well, but the 5800X3D is still showing 30–35W and 65–70°C while idle.