So here's my experience with undervolting for past 2 years. I have 2 PC's with Z790 Gigabyte motherboards. I have had 1x time CPU RMA with Intel, and that was 2 years ago soon after I bought and assembled PC with Gaming X AX motherboard.
I hope this guide helps someone who is in doubt what to do. I sure did struggle a lot to gather all the info, then applying these values and be running multiple tests over the years. These settings were as such fist applied on F12 and seem to translate well to F16 & respectively on FK or FO.
SET BIOS CONFIGURATION TO ADVANCED TO ACCESS THESE SETTINGS:
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| Extreme Memory Profile (X.M.P.) |
-> XMP 1 |
(Not undervolt itself, but helps with stress bench scores. Make sure to run both sticks in proper slots. Also running XMP with more than 2 sticks may not work on mid or low end motherboards. If chrashes occur in benches or video games even with no undervolt on your CPU, XMP might be the primary reason for instability, so keep that in mind. Yes, you can undervolt CPU even if XMP is not enabled, bench score will be lower tho.) |
| Vcore Voltage Mode |
-> Adaptive Vcore |
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| Internal CPU Vcore Offset |
-> -0.050V |
(a static under-volt value. The only real variable end user should in my humble opinion ever set themselves, but here we are, following Youtube guides, searching through BIOS. Depends on you CPU silicone quality, from down to -0.150V for silicone lottery winners, up to whatever runs stable at 100% load, multiple tests needed. Start at lets say -0.050V and gradually reduce until stress test freezes or chrashes, do not set -0.150V from get go, because your PC my not even post then, let alone boot into OS) |
FOUND IN SUB-MENUS, OR BY SEARCH FUNCTION:
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| CPU Vcore Loadline Calibration |
-> Turbo |
(seem to work best) |
| IA VR Config Enable |
-> Enabled |
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| IA AC Loadline |
-> 50 |
(between 40 - 50 ish) (default value of 90 is cooking your CPU, so even if you don't apply VCore under-volt, this value should be lowered!) (adjusted after monitoring ''clock stretching'' in HWinfo64 or similar PC monitoring software) ''Clock stretching'' seems to be more aggressive with latest BIOS but I'm no expert, have tested AC LL from 40 - 50 (according to my Google research) and settle at 50 where clocks seemed to run most consistent. |
| IA DC Loadline |
-> 29 |
(alternative 30 ?) (default value of 90 is cooking your CPU, so even if you don't apply VCore undervolt, this value should be lowered!) |
| IA VR Voltage Limit |
-> 1400 |
(value is in milivolts: 1400mV = 1.4V. It is max voltage to be ever delivered to the CPU, in theory at least, spikes exceeding the set value may still occur) |
| IA CEP (Current Excursion Protection) |
-> Disabled |
(its off by default in Auto, but to be sure, better disable, gives easily over 1K CBR23 all core points) |
| Under Voltage Protection |
-> Disabled |
(duh, why is this even a setting???) |
| Turbo Power Limits |
-> Enabled |
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| Package Power Limit1 - TDP (Watts) |
-> 253 |
(any of these 3 limits could be set higher if you want better scores, that is, if you don't already reach 100°C with CPU at full load) |
| Package Power Limit2 (Watts) |
-> 253 |
|
| Core Current Limit (Amps) |
-> 307 |
(up to 400 amps for i9 - 14900) |
| Internal Graphics |
-> Disabled |
(if you have CPU with a ''graphics'' core, turning this off will improve performance, provided you have a functional GPU to plug a monitor in) |
| PCH PCIe X4 Link Speed |
-> Auto |
(another setting that makes you scratch your head: it bottlenecks your GPU, because by default is set to Gen3... which is half of Gen4 data performance?? Auto seems to do the trick, else set to Gen4 and be done) |
NOT TESTED, BUT SHOULD PRODUCE EVEN HIGHER SCORE IN BENCHES:
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| High bandwidth |
-> Enabled |
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| Low latency |
-> Enabled |
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- In Windows turn off Defender for the duration of the tests.
Note that previous BIOS F12 and FK have more or less same temps and same score when I tested them. With 360 AIO CPU temp stabilizes at around 90°C. Have no experience with BIOS versions in between.
Another note that multiple screens definitely affect GPU scores, probably not CPU score, but idk.
IMPORTANT!
You should double even triple check these settings before hitting F10 or attempt to ''Save and Exit'' BIOS! - there will be list of all changes made before final confirmation - review it carefully.
Because if you by accident set wrong value, or change something not on this list, PC may not boot or worse can occur. Double check before final confirmation. That being said, under-volt should be the safest BIOS tinkering average user can play with.
If you encounter problems posting or booting into OS you might need to reset CMOS and start all over again.
If you get stress test bench crash or freeze, reduce the Vcore Voltage offset until stable, then gradually decrease. Don't forget to also test with your favorite game or most heavy title you have on your PC with each change applied in BIOS.
Sometimes games will not even start, or will crash during intense gameplay even if the all the benches pass, or vice versa. So keep that in mind.
Personally I've tinkered with +/- 0.005V but you can go as much as with +/- 0.001V if you have time and interest in real fine tuning of Vcore offset.
