[Xiaomi Mi 11i / 11X Pro / Redmi K40 Pro+] mslezak:
Just FYI, most people don't know what I'm talking about when I say "voltage regulators for the GPU." The goal here is to use the first one on the top of the list (top is lowest voltage, bottom is highest) that can support the frequency your GPU Mhz are defined at. As you go up a regulator, the voltage increases, which leads to more power usage and hotter temperatures. Note that I played with it a little bit, and it DOES NOT seem to allow large changes in frequencies (higher that is, without upping the regulator*** you may not be able to use the higher regulators because of a commit I found in KonaBess (noted later). So it's usefulness may be not as great as I had hoped on the OC side, the throttling side, yes this could be invaluable.

If it doesn't boot, ensure you have your fastboot ROM downloaded somewhere (or use the program, it will extract vendor_boot.img to the root directory for you, save off to your PC where fastboot is located as you'll have to use PWR+Volume Down to go to fastboot, then reinstall the original vendor_boot.img (the new format saves this info in this new partition) by typing:

fastboot flash vendor_boot vendor_boot.img

fastboot reboot

Now this tool looks great for underclocking. I booted at 295mhz low and 825mhz high without changing the voltage regulators. But note the program seems a bit buggy - it will (sometimes) drop the max clock when you change it, so you MAY need a kernel manager like SmartPack to set on boot the max clock speed. At least until the code is fixed. I was able to boot on a lower regulator at 150mhz BTW [LEVEL_LOW_SVS_D1], and I didn't notice any performance difference! Just watch out for dropped frames, which can happen if your spacing is too far apart, or your frequency clock not giving enough juice. This can be done just viewing the screen - set it how you like it - power hungry or power friendly or mix and match.

These are the GPU Voltage Regulator Names (extracted from Linux 5.6.41 K40 Pro Plus / Mi11i source, codenamed haydn), listed from lowest voltage to highest. You have 10 choices I believe (regulator 0 is always the max frequency, regulator 9 is the lowest frequency):

LEVEL_RETENTION (so low it may not display anything)

LEVEL_MIN_SVS

LEVEL_LOW_SVS_D1 (note: I got it to boot at 150mhz on this regulator)

LEVEL_LOW_SVS default for 315000000 (315mhz) [REGULATOR 9 STOCK]

LEVEL_LOW_SVS_L1 default for 379000000 (379mhz)

LEVEL_LOW_SVS_L2

LEVEL_SVS default for 443000000 (443mhz)

LEVEL_SVS_L0 default for 491000000 (490mhz)

LEVEL_SVS_L1 default for 540000000 (540mhz)

LEVEL_SVS_L2 default for 608000000 (608mhz)

LEVEL_NOM default for 676000000 (676mhz)

LEVEL_NOM_L1 default for 738000000 (738mhz)

LEVEL_NOM_L2

LEVEL_TURBO default for 778000000 (778mhz)

**LEVEL_TUBRO_L0 -> added by KonaBess, not sure you can actually use it as it would require a kernel modification

LEVEL_TURBO_L1 default for 840000000 (840mhz) [REGULATOR 0 STOCK]

The levels below are turned off by KonaBess on "old 888 firmware" in commit https://github.com/xzr467706992/KonaBess/commit/e12afa47c7255e5ce1d33d97700479f67449ff89 - I presume the K40 Pro Plus supports it as it has an 888+ qcom,speed-bin = <1> defined at 900mhz on the LEVEL_TURBO_L2 regulator in the file lahaina-gpu-v2.dtsi, while Mi11 code does not have this regulator defined in the file: qcom,rpmh-regulator-levels.h) NOTE: get fastboot up on your PC before you mess with any of these regulators, you'll need it! You'll be fastboot flashing vendor_boot.img a lot. The device is already super OC'd by Qualcomm stock. That's why 888's throttle so much. Now that may be GPU or CPU related, we don't know yet. This will give us some idea. Watch temps wisely:

LEVEL_TURBO_L2

LEVEL_SUPER_TURBO

LEVEL_SUPER_TURBO_NO_CPR (okay this regulator sounds scary - CPR is used to bring someone's heart back to life after it stops beating... use with EXTREME CAUTION. My guess is it turns off all overheating protection)

My K40 Pro Plus is packed up for resale, start a conversation with me if interested ($620 USD basically Mint condition + S&H, extra rugged case + cam lens tempered glass, no markup @ China price, Xiaomi.EU stable 12.5.3 rooted with Magisk Stable and has Vanced (YouTube and Music no ads), Netflix L1, Amazon US, AdAway, all Google Services and apps like Calendar, Contacts, Messages, Chome, Discovery, Lens, GPay always worked when I used the phone before, etc. just login to your Google account and everything will auto-setup). A guy said he'd buy it from me this Friday if I hold it for $700, we'll see about that. I know it works on T-mobile USA alright LTE (N41 5G IF deployed to your area, its not in Houston, TX yet for me to test) and many EU countries frequency coverage is even better. Start of conversation with me if interested I have loads of pics on other websites. Selling because I can only build so many kernels and I have way too many phones. **I'll delete this portion once sold, not sure if the XDA rules allow me to post it (sorry moderators if I violated a rule, just trying to give a great deal to someone who is looking for an 888, I'm not making ANY money).

Back to the topic at hand. I would begin starting at the 840mhz and switch it to one lower regulator, i.e. switch to TURBO instead, and likely drop the mhz too if it fails to boot. Then repeat the rest the same way (1 level down) but only modify 1 at a time, test, then it's fastboot time if it doesn't support it OR you succeeded (write down the numbers). Then run 3DBench 1 test run first. If that works fine, you can run the stress test for 20m after you're happy with all your new frequencies and see if it runs well (no fragments, no lag, etc). If so, keep it there. You should be able to see any FREQUENCY changes in SmartPack Kernel Manager (free on the Playstore or Github, under GPU menu). You can make up your own clock speeds too. I tried dropping the max clock to 825mhz from 840mhz and it booted fine; the AnTuTu v9.0.5-OB graphics segment was lag free. This is silicon lottery customization BTW, some chips will run better at different frequencies and regulators than others.

I hope you find this post useful, took me A VERY LONG TIME to put it together to simplify the GPU adjustments using KonaBess app. It's easiest to make small changes, remember OC'ing an already OC'd device (straight from QCOM, yes they OC'd it) is not likely to work work well - any OC attempts should be like +5000mhz or +10000 at a time. All 888 phones throttle on the default config when pushed hard enough (i.e. like during a bench / stress test session). Since you are mostly testing graphics, I suggest the 3DMark 20 minute stress test for stability verification. If you underclock the GPU enough, you can probably eliminate throttling while still getting a good bench result, while adding to your screen on time (SOT). Throttle free and fast, with decent battery, and you have a winner.

Although if you want to play with the often randomly changing AnTuTu benchmark, you can do that that a little bit faster. I just think that is used by OEMs to sell phones after using it for so many years, I noticed the version #s started to increment a lot faster as more 888 phones were released. From AnTuTu v9.0.1-OB to v9.0.5-OB scores just randomly seemed to change. Companies like RealMe and Nubia (RedMagic) cheat the bench anyway to give you higher scores that don't mean anything in actual use. 3DMark seems like a more consistent bench. Anyway, regardless of which bench you chooose, mark the first runs at the current settings. Let the phone cool down and close all open apps before benching (5 minutes is a good rule of thumb for all apps to load). For more consistency, turn on airplane mode and turn off bluetooth / nfc / etc. Try to run your benches at the same battery % (have that charger ready).

Please post your findings here and notate your device, the mhz you chose, the regulator you chose, etc. so people can work from your values. As I mentioned, you are testing your silicon lotto ticket here - most chips will differ between one another. Your 888 only has to pass a minimum spec to make it to production. Some are all stars and some barely make the cutoff. That's life, it's okay, they are all fast anyway. Even the worst chip will still be fast.

Feel free to like this post if it helped you out!