This is an automated archive made by the Lemmit Bot.
The original was posted on /r/homelab by /u/Vast-Boysenberry1662 on 2025-12-16 18:02:00+00:00.
I use a beastly Dell Precision 7820 with dual 20-Core Intel Xeon Gold 6138 processors and 64GB of DDR4 2666 Mhz RAM to crawl websites. I'm an SEO for large-scale publishers, so this machine is frequently needed to run Sitebulb, my favorite crawler, to crawl anywhere from 500,000 to 3,000,000 webpages. Having 80 threads (20 cores x 2 CPUS x 2 threads per core) is handy when each instance of Chromium needs to run on its own thread to load a page.
Sitting idle, this machine was using 220watts of power. That's a lot of power being drained for just reading a report after the big crawling action is done. But I found this can be reduced significantly with just software and BIOS tweaks.
Here are the steps I took:
Aggressive Core Parking (Registry Unlock)
Windows 11 hides the settings that control how many cores it puts to sleep ("Core Parking"), but you can unhide them to force the OS to aggressively park the second CPU.
Unhide the Setting:
• Open Registry Editor (regedit) as Administrator.
• Navigate to:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\PowerSettings\54533251-82be-4824-96c1-47b60b740d00\0cc5b647-c1df-4637-891a-dec35c318583
• Double-click Attributes and change the value from 1 to 0. (This unlocks the menu option).
Configure Power Options
• Reboot your machine.
• Go to Control Panel > Power Options.
• Select the "Balanced" plan (Do not use High Performance).
• Click Change plan settings > Change advanced power settings.
• Expand Processor power management. You will see a new option: Processor performance core parking min cores.
• Set this to 10%.
At 80 threads, setting this to 10% told Windows to keep 8 threads active, and park the other 72. This effectively forces my second CPU into a coma until a massive workload (that exceeds the first CPU) comes along.
BIOS Settings
- Enable Intel SpeedStep: This allow clock rates to be adjusted up and down.
- Enable C-State: This is critical. It allows the CPU to sleep when idle. Without this, your "Core Parking" Windows tweaks will do nothing.
- Disable SATA Controller: I'm only using M.2 in this system. By disabling the SATA controller, I saved 10 watts.
- Audio: Uncheck "Enable Audio Controller"
- Serial Port: Uncheck "Enable Serial Port"
Admittedly, the audio and serial port savings are negligible, but so long as I was mucking around in the BIOS I disabled anything I could think of.
After all these changes, total consumption at idle dropped from 220watts to less than 140watts, so a total savings of 80watts at idle. I don't run this machine 24/7, but if I did this would amount of over $200/year of consumption here in New Hampshire, where rates are relatively high.
If you have a dual CPU machine or even a single CPU machine with a high core count I think this is worth doing. More money to put toward a new NAS!
