How do I reduce power limit throttling and current limit throttling on my 8750H CPU?

JohnFrantzen

I just recently recieved my Acer Predator Helios 500 with an i7 8750H processor and although I am extremely pleased with it in general I have noticed some CPU issues.

First I noticed the CPU thermal throttling during long gaming sessions with the fans set to auto, easy fix would of course be to just set fans to max, but at a point when I was playing with my nephews I couldn't use a headset which means the fan noise was a real issue when they were set to max.

So I decided I wanted to investigate options to improve my thermals, firstly I thought of re-pasting, but I don't want to void my warranty so I asked the retailer what it would cost to have them do it, they explained that they don't do that themselves so they'd have to send it to a third party and thus the cost would be quite steep, over $50....that just didn't feel right to me so I went ahead to research other options.

This lead me to attempt undervolting, I downloaded XTU and after some online research I think -150 is the sweet spot for this laptop.
I noticed some heavy RAM usage which I at first thought was the software, but later discovered there is an issue with this laptop where the PSAgentAdmin process will start draining all your RAM if you leave it on for a while.
The soluition was to go into Services, find the Killer Network Service and change one of the options to not do anything the first time the service fails (before that it kept trying to relaunch constantly eventually draining all the RAM).

However from the XTU software I've noticed the CPU easily Power Limit Throttles and Current Limit Throttles during load, while this might not really be a big issue at all it annoys me now that I know of it and I would very much like to know how I can reduce or even completely avoid this from happening.

Anyone know what causes it and what I can do to address it?

Here are the settings I've found give me the best benchmark score from the built-in benchmarking tool in XTU.



I did reach 4,01 GHz max processor frequency during one of the runs (I believe that was with -145 V).
It seems the default settings was automatically set to my earlier XTU settings after my laptop updated Windows earlier today, the XTU software was running when I clicked "Restart now" which I believe is why those settings were set to default or maybe there is another reason...idk :P 

On Cinebench I got a score of 1103 which I guess is....decent?

Red-Sand

Acer just added boosted power package levels to the Helios 500 Predator Sense!!!

70w!!!!

Jack22

Please check on this

JohnFrantzen

Thanks for replying, but I guess I don't understand what you want me to see?

I can see you undervolted your cpu core a little more than me and less on cpu cache, as that is something you can do on throttle stopper and not XTU, but you're still power limit throttling...is this how you avoid current limit throttling?

Your Cinebench score seems really low btw, maybe you undervolted too much and/or boosted too little?

Please explain what you want me to check as I am not familiar with these things, I just started researching it for the first time yesterday :P

MrGrudev

Dont use both XTU and Throttlestop at the same time. Return everything on XTU to 0. Remove the ThrottleStop.ini file. Turn off your PC, turn in pack on. Then try to undervolt the CPU core and cache in the FIVR in the Throttlestop. Set SAME undervolt settings on core and cache. Mine 8750H is stable at -135 mV. I set my turbo ratio limits on 38. Sacreficing 100 Hz, which is not a big deal for that CPU I managed to maintain 3.8 Ghz on 45W power. If you dont go over 45W you will not experience power limit throttling. Otherwise the default limit is 56W for 28 seconds and the returns to 45W.

Good luck!

lilenday

I also have power limit throttling with -140mv undervolt. If you want hit constant 4.0ghz without power limit throttling, I don’t think there’s a solution yet. It has to do with firmware being locked. If there’s a way to bypass it then you won’t have this problem. I don’t think anyone who has the 8750h had any success running this chip to its full potential without being power limit throttled.

sri369

@JohnFrantzen
100% capacity run puts tremendous load on power usage and heat generation. This kind of power pulls are supported pretty much in surges for a few seconds. Some things you could do to lower temps is to adjust your FPS to the max your screen supports, and using Throttlestop to limit power to processor.
I wouldn't bother too much about benchmark scores; if a laptop performs well to serve my needs I am good. Pushing too much towards benchmarks isn't apt either since, with the same specs, your system might be slower than someone else's.
Put it like this... we both have exact same systems... and i have search indexer disabled. And this makes a ton of difference in benchmark results.

To limit thermal throttling here's what I did:
1. Increased the height of laptop base by about an inch using felt pads under four feet.
2. Limit FPS to 60 (my screen supports 60 max).
3. Use ThrottleStop.
4. Use USB fan for extended heavy gaming sessions.

JohnFrantzen

MrGrudev said:

Dont use both XTU and Throttlestop at the same time. Return everything on XTU to 0. Remove the ThrottleStop.ini file. Turn off your PC, turn in pack on. Then try to undervolt the CPU core and cache in the FIVR in the Throttlestop. Set SAME undervolt settings on core and cache. Mine 8750H is stable at -135 mV. I set my turbo ratio limits on 38. Sacreficing 100 Hz, which is not a big deal for that CPU I managed to maintain 3.8 Ghz on 45W power. If you dont go over 45W you will not experience power limit throttling. Otherwise the default limit is 56W for 28 seconds and the returns to 45W.

Good luck!

I'm only using XTU for now, if I really need to do something that I can't do here then I guess I will uninstall it and download Throttlestop instead, but it doesn't seem like it's necessary, just feels a bit more intimidating using that since there are so many things you can adjust and I have no idea what half of them do or how they can potentially destroy my laptop.

My CPU seems totally stable at -150 undervolting, I will probably try -155 later when I wont mind leaving it on a 1h+ stress test, right now I wanna use it and I don't wanna do it over night or when I'm not home.

Don't know how/where I can set my "Turbo ratio limit", but it sounds very similar to the "Maximum turbo boost limit", is it the same?

I attempted setting both PL1 and PL2 to 45W and ran a benchmark test, it still seemed to power throttle just as often only now it mostly ran on max core frequency 3.30 GHz and power throttled down to about 2.75 GHz, while on 100W/115W settings it mostly sits around 3.55 GHz and power throttles down to around 3.12 GHz....my temps aren't an issue anymore after I fixed the problem with Killer Network Services constantly restarting.

So I guess I'll just keep it on these settings as it just seems better to have higher power boost limit even tho it should in theory power throttle more, it seems to power throttle just as often on lower power boost limit and then it even throttles to a lower frequency as well as averaging at a lower frequency.

I guess I'll just have to wait and hope they will give us a firmware update that increases the power limit set for the CPU or if anyone know about a video or a detailed explanation (preferably with pictures) on how to do this in the BIOS on a system like mine I would very much appreciate a link

JohnFrantzen

sri369 said:

@JohnFrantzen
100% capacity run puts tremendous load on power usage and heat generation. This kind of power pulls are supported pretty much in surges for a few seconds. Some things you could do to lower temps is to adjust your FPS to the max your screen supports, and using Throttlestop to limit power to processor.
I wouldn't bother too much about benchmark scores; if a laptop performs well to serve my needs I am good. Pushing too much towards benchmarks isn't apt either since, with the same specs, your system might be slower than someone else's.
Put it like this... we both have exact same systems... and i have search indexer disabled. And this makes a ton of difference in benchmark results.

To limit thermal throttling here's what I did:
1. Increased the height of laptop base by about an inch using felt pads under four feet.
2. Limit FPS to 60 (my screen supports 60 max).
3. Use ThrottleStop.
4. Use USB fan for extended heavy gaming sessions.

I don't really have a problem with thermals and Acer Predator Helios 500 comes with G-Sync

lilenday said:

I also have power limit throttling with -140mv undervolt. If you want hit constant 4.0ghz without power limit throttling, I don’t think there’s a solution yet. It has to do with firmware being locked. If there’s a way to bypass it then you won’t have this problem. I don’t think anyone who has the 8750h had any success running this chip to its full potential without being power limit throttled.

I think you're right, but I hope someone has managed to adjust the power limit set without changing to a self-modded BIOS :P

Red-Sand

Power limit throttling is how these 8th gen CPUs were designed.

I played with a MSI with a 8th gen i7 that had a package power cap of 90 but the CPU only utilized 64w and it STILL didnt break 1k cinebench. I think the package power and whatever Acer did works quite well.
I think I managed 12XX on cinebench once?

Anyway. The main diffrence between XTU and Throttlestop is that XTU is 40+MB in size and Throttlestop is 600kb in size. So a very light footprint.

The BEST feature of throttlestop is the ability to adjust speed shift epp (energy performance profile) which dictates how aggressively the CPU boosts its clock speeds.
Unfortunately Throttlestops developer hasnt been able to update his software due to lack of information released by intel. Speed shift still works but not as well as it does on the HQ CPUs.

Overall Throttlestop will handle temps better then XTU and also with less bloat.

Red-Sand

Acer just added boosted power package levels to the Helios 500 Predator Sense!!!

70w!!!!

Red-Sand

Legend! 😁😁😁

JohnFrantzen

IT WORKED!



I just ran windows updates which included the update to Predator Sense and restarted my laptop, I then had this option to adjust the power limit to my CPU, I set it to high (not max), applied my XTU settings and ran the built-in benchmark.

Where it used to power throttle a lot during this benchmarking (even without any adjustments made with XTU) it now didn't power throttle ONE TIME!  
THANK YOU ACER! 

PS: I increased the power boost max quite high compared to what I've seen others do and while I am tempted to push it even higher as well as use the max setting on power limit for CPU, I got a notification from XTU when I applied the settings that it no longer supports the watchdog feature so if my laptop would crash...well I would not know how to fix it...not sure if it matters or not as I don't have XTU set to launch on startup, but I'd rather be on the cautious side with a machine as expensive as this one ;P

Red-Sand

JohnFrantzen said:

IT WORKED!



I just ran windows updates which included the update to Predator Sense and restarted my laptop, I then had this option to adjust the power limit to my CPU, I set it to high (not max), applied my XTU settings and ran the built-in benchmark.

Where it used to power throttle a lot during this benchmarking (even without any adjustments made with XTU) it now didn't power throttle ONE TIME!  
THANK YOU ACER! 

PS: I increased the power boost max quite high compared to what I've seen others do and while I am tempted to push it even higher as well as use the max setting on power limit for CPU, I got a notification from XTU when I applied the settings that it no longer supports the watchdog feature so if my laptop would crash...well I would not know how to fix it...not sure if it matters or not as I don't have XTU set to launch on startup, but I'd rather be on the cautious side with a machine as expensive as this one ;P

There are 3 XTU profiles in C:/Program data/OEM/PredatorSense/"your cpu"
You can open these and change the values to your liking although Acer did an awesome job at the limits.

Normal: Stock TDP (45 & 56)

Fast: Long boost at 45w
Short boost at 70w

Turbo: Long boost at 56w
Short boost at 70w

I tested increasing package power to 90w and the CPU capped itself at 71.8w. So the setting of 70w is perfect.

On top of all that each profile has a built in -0.125 undervolt.
I managed to change the UV to -0.150 (a good value for my laptop)
Once I updated each profile I exported them via Profile options in XTU and named them the same as their profiles (Normal, Fast, Turbo) and saved their profiles to another folder. I then added my new UV profiles to the PredatorSense folder and now I boot with an auto UV and increased package power limits. 😁😁

You do NOT need any undervolting software as the "XTUSERVICE" service thats run by predator sense is a small XTU executor. 

So once I tweaked the profiles with XTU I uninstalled XTU and everything still runs perfectly!

My Predator Sense undervolts and manages unlocked package power limits!!!

Sttooooooked

M4rdock

Lol lol nice findings Sand!
Looks like Acer engeniers are lurking here and fixed only complaint everybody had with this laptop.

Btw. Is turbo 100% safe for cpu lifespawn?

Red-Sand

M4rdock said:

Lol lol nice findings Sand!
Looks like Acer engeniers are lurking here and fixed only complaint everybody had with this laptop.

Btw. Is turbo 100% safe for cpu lifespawn?

As long as temps are good then yes

sri369

M4rdock said:

Btw. Is turbo 100% safe for cpu lifespawn?

Only in bursts, and not for extended periods of time!

Red-Sand

sri369 said:

M4rdock said:

Btw. Is turbo 100% safe for cpu lifespawn?

Only in bursts, and not for extended periods of time!

This is not accurate.

In something like a game where processes change frequently you'll find your short boost clocks constantly running since they do not remain on a specific task for over a period of 28 seconds.

Also this feature was added by Acer's engineers.. not manually done.

KayakNate

First post here. Sorry to resurrect an old thread. I really want to buy this laptop, but haven't been able to resolve this issue yet. 

I spent 3 hours messing with a demo at Micro Center. I updated to the latest predator sense, turn cpu to max, undervolted with xtu, but still get power limit throttling and terrible scores in cinebenvh while the processor is only around 80C. Cinebenvh scores just over 800. 

This makes no sense. The Asus Zephyrus will thermal throttle at 95C because it has worse cooling, but still gets score of 1200ish because it doesn't thermal throttle as much as helios power throttles. 

So this post makes it sound like it's fixed. But it doesn't seem like it is to me. Or I'm misunderstanding.

Please help. Other than power throttling, this laptop is exactly what I'm looking for. And is only $1700 right now. 

MohaSyrMK

I have the same power limit throttling but I have what is worse than that, I have thermal throttling, my cpu jumps to 97C as soon as I run any stress test or benchmark. my fans spin like crazy. I sent it to acer services and somehow they said your laptop is fine, LOL. so I decided to repaste it myself and void the warranty which is -in my opinion-  useless. the thing is, I undervolt to -.150 and I got 1239 CN score. even though I was thermal throttling so bad. Idk if I could go higher if I repaste but I will check that once I decide to repaste and do it. 

@Red-Sand

can you please tell us more how to get your undervolt and power stuff ready from predator sense with some pictures how to do it. it would be amazing if the undervolt and power limit can be done without any programs installed or running in the background. 

KayakNate

MohaSyrMK said:

I have the same power limit throttling but I have what is worse than that, I have thermal throttling, my cpu jumps to 97C as soon as I run any stress test or benchmark. my fans spin like crazy. I sent it to acer services and somehow they said your laptop is fine, LOL. so I decided to repaste it myself and void the warranty which is -in my opinion-  useless. the thing is, I undervolt to -.150 and I got 1239 CN score. even though I was thermal throttling so bad. Idk if I could go higher if I repaste but I will check that once I decide to repaste and do it. 

@Red-Sand

can you please tell us more how to get your undervolt and power stuff ready from predator sense with some pictures how to do it. it would be amazing if the undervolt and power limit can be done without any programs installed or running in the background. 

How are you getting 1239 on CN/CB?! And those temps make it seem like your CPU isn't wattage throttling at all. Which is great. If I could get a helios to do what yours is doing, it would be an instant purchase. What settings are you using one what cpu softwares?

Red-Sand

MohaSyrMK said:

I have the same power limit throttling but I have what is worse than that, I have thermal throttling, my cpu jumps to 97C as soon as I run any stress test or benchmark. my fans spin like crazy. I sent it to acer services and somehow they said your laptop is fine, LOL. so I decided to repaste it myself and void the warranty which is -in my opinion-  useless. the thing is, I undervolt to -.150 and I got 1239 CN score. even though I was thermal throttling so bad. Idk if I could go higher if I repaste but I will check that once I decide to repaste and do it. 

@Red-Sand

can you please tell us more how to get your undervolt and power stuff ready from predator sense with some pictures how to do it. it would be amazing if the undervolt and power limit can be done without any programs installed or running in the background. 

I'm actually doing this on the Helios 500, is that what you have @MohaSyrMK?

If its not then there is a special procedure to hijack Predator Sense's XTU service to gain a undervolt without running any other programs (auto start with pred sense).

I plan on making videos for both methods soon.