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- Jul 21, 2022
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| System Name | HP 15-cs0000ne |
|---|---|
| Processor | I7-8550U -115mv core+cache |
| Memory | 16GB Samsung 2400Mhz |
| Video Card(s) | MX150 4GB 25W + Intel UHD 620 |
| Storage | 128GB NVME SSD + 500GB WD Blue SATA SSD |
| Mouse | Logitech G102 Lightsync |
| Keyboard | CosmicByte CB-GK-18 Lubed with krytox 205g0, Clipped, Band-aid modded, Foam modded |
| Software | ReviOS Windows 10 + Arch Linux |
| Benchmark Scores | CB R23= 4600, CB R25= 773 |
I wrote this guide for to the hundreds of people having the same problem and got no where. This is the same as the guide I wrote on reddit here
This guide is for people like me who have an i7-8550U (or any u series chip), which can turbo boost to 40 Watts, and then suddenly are hard limited to 15 Watts after some time, regardless of temperature. This is due to an EC set Long PL, and nothing you do in the BIOS or Throttlestop can change it. This leads to some heavy performance loss, even though, temps are in 60s . For the past one week, I tried everything possible to unlock the limit, with modding the bios, throttlestop, etc. However, even that didn't work, as the limit is still controlled by the EC.
So, I gave up trying to unlock the tdp, until, I stumbled upon a setting called IMON slope. Basically, instead of unlocking the limit itself, it makes the cpu report a false power consumption to the EC. The value is a percentage of the actual consumption of power it will report to the EC. So, if you set it to 50, it will report half the actual consumption, which basically bypasses the limit, and lets it use twice the power.
GUIDE STARTS HERE:
View attachment z86zthoa42c91.webp
View attachment k29vqvbo52c91.webp
View attachment n97bsipoh2c91.webp
RESULTS + additional performance tip:
On the first throttle stop benchmark, Power Usage immediately went to 20W(40W) and stayed like that for much longer than it normally would, while temperature skyrocketed to to 98C and it started thermal throttling. This was no good. However the long power limit, was now 30W, Previously, this CPU could only sustain around 2.2ghz. Now it can do 3.2Ghz indefinitely, with temps reaching about 85C . I still wasn't satisfied and wanted more. I then undervolted my core to -225 and cache to -140 .(This is a very extreme undervolt, and you most likely wont be able to apply this, I got extremely lucky.) .
I have never seen such a drastic performance boost from an undervolt in my life. The short power stayed at only 15W(30W) and still turbo'd to the max frequency. This meant, I can now reach max turbo with only 30 W with this undervolt. temps never exceeded 85. This also meant that I can reach max turbo with my long power limit of 15W as well, without thermal throttling. This pretty much means, I can indefinitely run at 3.7Ghz at all cores with temps below 85C, from the previous 2.3Ghz. If your temps are decent, but you still cannot achieve max frequency, then lower your imon slope further.
NOTE: Your results might vary significantly to mine, due to the cooling. This processor is found on many thin and light laptops with not enough cooling solution and may not be able to sustain full turbo like mine did. I have a somewhat thick 15 inch laptop, which I have repasted, which could be the reason behind my impressive thermals.
Benchmarks:
TS bench 120M = 22 > 18 (not much difference since long power limit activates at the end of this test)
TS bench 960M = 243 > 151
Cinebench R15 = 580 > 773 (almost a 4770k in my notebook with a 5 year old processor using 30W)
Cinebench R23 = 3400 > 4600 (comes very close to 28W i7-1165G7 and demolishes the 15W variant)
CPU - Z = 84% reference to 4790k > 96% reference to 4790k
Average FPS in valorant on 1080p low with MX150 = 120 < 150
Conclusion : You can get some serious sustained performance boost doing this, and I highly recommend you do it, provided your laptop can handle the thermals.
EDIT : turns out, my undervolt isn't very stable during actual gaming, so I have reduced it to 100mv. I can no longer full turbo at 30W. I also discovered that in my particular laptop, reducing imon slope below 50 doesn't do anything. therefore I instead applied a -5W to the Imon offset.(you need to change both imon offset prefix and imon offset in all 4 sections) . However this has significantly increased my heat, and my laptop starts throttling after a minute of constant 3.7ghz, and it throttles due to VR overheating, and it fluctuates constantly between 2.4 and 3.7 as the VR desperately tries to cool itself. this hits performance pretty hard. Therefore, I reverted back to the 30W limit and decided to live with constant 3.4ghz turbo instead, which yields better performance than just leaving it unlocked.
This guide is for people like me who have an i7-8550U (or any u series chip), which can turbo boost to 40 Watts, and then suddenly are hard limited to 15 Watts after some time, regardless of temperature. This is due to an EC set Long PL, and nothing you do in the BIOS or Throttlestop can change it. This leads to some heavy performance loss, even though, temps are in 60s . For the past one week, I tried everything possible to unlock the limit, with modding the bios, throttlestop, etc. However, even that didn't work, as the limit is still controlled by the EC.
So, I gave up trying to unlock the tdp, until, I stumbled upon a setting called IMON slope. Basically, instead of unlocking the limit itself, it makes the cpu report a false power consumption to the EC. The value is a percentage of the actual consumption of power it will report to the EC. So, if you set it to 50, it will report half the actual consumption, which basically bypasses the limit, and lets it use twice the power.
GUIDE STARTS HERE:
- Before proceeding, first go check your bios, to see if you have a setting to adjust IMON slope. Its pretty unlikely on locked down laptops, but it doesn't hurt to check. If you have an unlocked bios or access to advanced settings, its pretty likely you have it. If you have it, then great. Set it to a percentage of your choice and you are done.
- If you are like me and don't have the option, you need to modify the option through EFI shell. Download UEFI Tool, IFR extractor, RU.efi, and UEFI Shell, and your bios.bin/biosfd . On HP laptops, you can obtain it through the third option "Copy" . You can find the platform ID in the bios. password for RU.efi is 1010223830646
- Open UEFI tool, and drag your bios onto the main window, or click on file>image>your bios file.
- press control+f and click on "Text" . Now search for "IMON' . you should have many results. double click on them and make sure all of them are from the same parent(DriverSampleDxe). If it isn't you may have to repeat it on each one.
View attachment z86zthoa42c91.webp
- Right click on the parent, In my case it is DriverSampleDxe and click on extract as is . Save it somewhere.
- Open IFR extractor, and select the file you just saved. now select the destination location.
- Open this file and press ctrl+f and type in IMON Slope.
- You should find 4 occurences, these are for core, system agent, gt slice and unslice. (you need to change all of them or it wont work)
View attachment k29vqvbo52c91.webp
- Note the Var offset of each of them. In my case it was 0x148, 0x149, 0x14A and 0x14B.
- It should most likely be in CpuSetup, which is in varstore 0x3, if it isnt, then find out the name of your varstore, from the first few pages of the file.
- Go here and type the percentage you want in the decimal number section. This will convert it into hex. (common values are - 25 = 19, 50 = 32, 75 = 4B , which will set your max long tdp to 60, 30 and 20 respectively(when long PL is 15). Choose the value, keeping in mind your cooling capability. We are increasing heat way beyond what it was initially designed for)
- In my case, temps never went above 65 when I stress tested with 15W TDP, which means my laptop can handle a lot more power. So, I went with 50 percent.
- Now we are ready to change the values, in the EFI shell. Format a fat32 USB. rename the UEFI shell we downloaded to bootx64 and place it EFI/boot directory. (unnecessary if your PC allows you to manually boot EFI files.)
- Now place RU.efi at the root of the USB.
- Reboot into bios, and disable secure boot.( also change boot order to boot USB if your laptop wont let you select boot device on startup)
- Enter your boot device selection screen and select the USB, or manually select bootx64.efi (F9 on most HP pavillion laptops)
- Wait for 5 seconds until you get a shell, and type "ru" and click enter. Press any key to get rid of the warning
- Press alt + = , you should have a list of Options. We are looking for CpuSetup (could be different, but very unlikely)
- Once in CpuSetup, Use pg+down or pg+up to scroll through the pages. The rows are the first one or two characters, and the columns are the last character. For example, 0x148 is row 0140 and column 08 .
- Edit each variable you found earlier to the value you found earlier. I used 32 . In my case all 4 variables were next to each other, so it made it a lot easier.
View attachment n97bsipoh2c91.webp
- After editing all of them, press control + w , to save the settings, and wait for the confirmation prompt. press alt+q to exit and press power button to shut down. Remove the USB and turn on your PC.
- To confirm it works, open throttle stop, and run TS bench, while its using short power limit it should say half of what it usually uses while still running at full clock speeds before eventually thermal throttling. in my case it was at 20 which means its running at 40W.
- That's it, you have pretty much doubled your sustained performance.
RESULTS + additional performance tip:
On the first throttle stop benchmark, Power Usage immediately went to 20W(40W) and stayed like that for much longer than it normally would, while temperature skyrocketed to to 98C and it started thermal throttling. This was no good. However the long power limit, was now 30W, Previously, this CPU could only sustain around 2.2ghz. Now it can do 3.2Ghz indefinitely, with temps reaching about 85C . I still wasn't satisfied and wanted more. I then undervolted my core to -225 and cache to -140 .(This is a very extreme undervolt, and you most likely wont be able to apply this, I got extremely lucky.) .
I have never seen such a drastic performance boost from an undervolt in my life. The short power stayed at only 15W(30W) and still turbo'd to the max frequency. This meant, I can now reach max turbo with only 30 W with this undervolt. temps never exceeded 85. This also meant that I can reach max turbo with my long power limit of 15W as well, without thermal throttling. This pretty much means, I can indefinitely run at 3.7Ghz at all cores with temps below 85C, from the previous 2.3Ghz. If your temps are decent, but you still cannot achieve max frequency, then lower your imon slope further.
NOTE: Your results might vary significantly to mine, due to the cooling. This processor is found on many thin and light laptops with not enough cooling solution and may not be able to sustain full turbo like mine did. I have a somewhat thick 15 inch laptop, which I have repasted, which could be the reason behind my impressive thermals.
Benchmarks:
TS bench 120M = 22 > 18 (not much difference since long power limit activates at the end of this test)
TS bench 960M = 243 > 151
Cinebench R15 = 580 > 773 (almost a 4770k in my notebook with a 5 year old processor using 30W)
Cinebench R23 = 3400 > 4600 (comes very close to 28W i7-1165G7 and demolishes the 15W variant)
CPU - Z = 84% reference to 4790k > 96% reference to 4790k
Average FPS in valorant on 1080p low with MX150 = 120 < 150
Conclusion : You can get some serious sustained performance boost doing this, and I highly recommend you do it, provided your laptop can handle the thermals.
EDIT : turns out, my undervolt isn't very stable during actual gaming, so I have reduced it to 100mv. I can no longer full turbo at 30W. I also discovered that in my particular laptop, reducing imon slope below 50 doesn't do anything. therefore I instead applied a -5W to the Imon offset.(you need to change both imon offset prefix and imon offset in all 4 sections) . However this has significantly increased my heat, and my laptop starts throttling after a minute of constant 3.7ghz, and it throttles due to VR overheating, and it fluctuates constantly between 2.4 and 3.7 as the VR desperately tries to cool itself. this hits performance pretty hard. Therefore, I reverted back to the 30W limit and decided to live with constant 3.4ghz turbo instead, which yields better performance than just leaving it unlocked.
Last edited:
