The CPU speed remains locked at 800MHz in Windows, while it functions normally in BIOS and Safe mode.
The CPU speed remains locked at 800MHz in Windows, while it functions normally in BIOS and Safe mode.
Hi, I'm trying to resolve an issue with my CPU that's stuck at 800Mhz/0.79Ghz. The system is running the Gigabyte Z590 Aorus Master board. Everything seemed normal until I updated Windows 10 this evening. After the BIOS reset, I removed the CMOS battery, unplugged all components, and held the power button for 30 seconds before reconnecting everything.
I checked Cinebench results and temperature/power usage were low according to hwinfo65, cpuz, coretemp, and Task Manager. In Safe Mode with Task Manager, CPU usage was reported at 2.8Ghz, but the performance tab showed full CPU utilization. The BIOS displayed a reading of 4600Mhz.
Hwinfo64 indicated three possible fixes: "IA: Turbo Attenuation", "IA: Electrical Design Point.Other (ICCmax,PL4,SVID,DDR Rapl)" and "Ring: Max VR Voltage, ICCmax, PL4". I tried disabling "BD PROCHOT" in Throttlestop but it didn’t help.
I also checked the Limits option—my Core i9-10900 was highlighted red, and under EDP OTHER GPU, the blank field made me confused. In FIVR PL4, voltage mode showed 0 and offset was empty.
I’m not sure how to share screenshots, but any additional details would be useful.
Also consider verifying the MMIO Lock box within the ThrottleStop TPL window. Share some screenshots using imgur or a comparable platform. Another user experienced the same issue recently; it seems a recent update might have caused this. IccMax for both the core and cache should reach their maximum values, which is 255.75. Setting PL4 to 0 is acceptable, indicating the PL4 limit isn't active.
TPL power limit controls settings are adjusted. Disable controls checkbox is selected, and all other options remain unchecked, including sync MMIO. In the miscellaneous section, everything is unchecked, and the PP0 turbo Time limit slider is positioned to the left (lowest setting). Raising IccMax in the core from 1 to 255.75 resolved the problem; if you set the cache section to 255.75 as well. The IccMax value shown in the system agent section is 20.00—should I update that? When I click on limits, the EDP OTHER under core and RING still displays the same information, but now in yellow—what does that mean? Every time I restart the PC, these settings need to be changed; is there a permanent solution? Do you have any guidance or explanation about these values? Also, I’m curious why this didn’t impact safe mode.
IccMax on the core and cache should match in value. If you adjust the core to 255.75, the cache should reflect the same setting. When you initially launch ThrottleStop and it doesn’t locate a prior ThrottleStop.INI file, it will apply default CPU values. If it previously indicated IccMax was only at 1.00, this would lead to severe EDP throttling, forcing the CPU to operate at its slowest. This suggests either the BIOS isn’t setting IccMax properly or there’s an issue in Windows. Typically, the BIOS is responsible for this error.
I don’t have experience with your Gigabyte motherboard. Check the BIOS settings for IccMax and adjust it to 255.75. A Z590 board should allow this change. Some budget boards may not support modifying IccMax in the BIOS. After making any BIOS changes, remove the ThrottleStop.INI file before running ThrottleStop so it can read the updated IccMax from the CPU.
Only modify ThrottleStop settings if they resolve your issue. The standard System Agent IccMax is around 20.00, which appears fine. The incorrect core and cache setting is what’s causing throttling. If you locate IccMax in the BIOS, it likely only needs adjustment for one value. Although the core and cache are separate in the CPU, most BIOS versions automatically assign the same IccMax to both registers.
Many monitoring tools and stress tests may behave unpredictably in safe mode. Ignore any reported CPU speeds in this state—it’s often just a random number without real meaning.
Red boxes in Limit Reasons indicate active throttling, which is undesirable. Performance is being reduced.
Yellow boxes suggest previous throttling events. Some systems may show a few yellow boxes during startup. These are warnings; you can usually disregard them as long as the CPU runs at its rated speed without throttling.
If IccMax is found in the BIOS, that’s a permanent solution. The default 1.00 value written by the BIOS is likely a bug introduced by the developer. IccMax should never be set to 1.00. Ensure you’re using the latest stable BIOS version. This issue is fairly common and is usually fixed quickly once reported.
In safe mode, nothing functions perfectly. Disregard any testing you performed in safe mode. You understand what’s causing your throttling problem and know how to resolve it—either by tweaking IccMax in the BIOS or using ThrottleStop.
If you have solid cooling and aim for peak performance, adjust the PL1 power limit in the BIOS from 65 to at least 150. I’ve set a similar board (10850K) to 300W for both PL1 and PL2. The default 65W recommendation from Intel will greatly limit the maximum performance of a 10900.
Here’s how I reduce power limit throttling.
Thanks for the update! I'm still searching for the IccMax setting in my BIOS without success. I've checked the manual and tried the menu multiple times, but I'm not finding it anywhere else. I'll keep trying until I locate it.
My Asus BIOS labels this option,
CPU Core/Cache Current Limit Max.
It is one setting that sends identical values to both the core and cache iccMax registers.
I just reviewed the manual for your motherboard. The full-featured BIOS contains numerous settings, but I couldn’t locate anything related to current. It’s likely the IccMax setting isn’t present in the BIOS.
You may need to implement ThrottleStop via the Task Scheduler to address this issue. Adding it to your Windows startup routine is straightforward. Here’s a helpful guide for that.
I believe that. Give it a try and see what happens. Remove the ThrottleStop.INI file once you've adjusted the BIOS settings. This will allow ThrottleStop to use the updated CPU value. I configured it to 255.75 to prevent throttling.