Undervolting i7-8750H

Sklero

@MrGrudev
Max i got was -175mv, however it wasnt stable enough - it could crash even after 3h of gaming.
i use -165mv now, played yesterday Path of Exile (all the time uses 80-100% GPU, and same for CPU), and didnt have any crashes after playing it for 4 hours.

But my scores are around 1170-1220pts on Cbench 15, so not bad either, the best I read was to reach 1260pts or so on i7 8750H

Red-Sand

Sklero said:

@MrGrudev
Max i got was -175mv, however it wasnt stable enough - it could crash even after 3h of gaming.
i use -165mv now, played yesterday Path of Exile (all the time uses 80-100% GPU, and same for CPU), and didnt have any crashes after playing it for 4 hours.

But my scores are around 1170-1220pts on Cbench 15, so not bad either, the best I read was to reach 1260pts or so on i7 8750H

I found the best stable value to be -0.140 core/cache for the i7-8750H and didnt hinder performance either.
I actually have my temps increase if I go lower... not sure why

Sklero

@Red-Sand

Oh, that temp increase is weird, maybe it gets too low energy that it has to use more power in order to get the performance, so the heat rise up ? 
I will try now myself -140 and see if I will have any changes

Sklero

@Red-Sand
So I cinebenched:
-140mv - around 1120pts
-160mv - around 1180pts

Path of Exile - unlocked FPS cap so it would drain as much CPU/GPU possible 30min gameplay on each:
-140mv - ranged on around 76-80 degrees on CPU and 68-70 on GPU
-160mv - Degrees are around 78-82 degrees on CPU 68-70 for GPU

All on max vents (so that everything is the same) in PS and a cooling pad

Dunno what to think about this

Eshanoy167

Hey guys, 
I have a question which I really want to know the answer for, Do any of you experience crashes on the same undervolt as you have on plugged in while its running on battery?

For example:- A -140.6 mv is stable when plugged in, But if its plugged out and on battery , It crashes after a while.

MrGrudev

Its would be normal if it crashes on power and not on battery. But in your case I don't know what might be the reason. What are your settings on battery and plugged in? In throttlestop, windows power options.. You can find the answer there. 

Eshanoy167

MrGrudev said:

Its would be normal if it crashes on power and not on battery. But in your case I don't know what might be the reason. What are your settings on battery and plugged in? In throttlestop, windows power options.. You can find the answer there. 

The windows was always in High Performance mode, Other than that, There arent anythings which I think have been done. So according to you its normal when the laptop crashes when its plugged in, but its abnormal when it crashes when its plugged out? Im going to try running it on balanced and see if it makes a difference later.
Thanks for the quick reply man

MrGrudev

No its not normal to crash at all, but it makes more sense if it crashes on power, rather that battery. Because on power, the power delivered to the CPU and GPU is much more than on battery. So if the undervolting is too much it might be a problem. 
If you have any crashed, my suggestion is to reduce the undervolt value a little bit. My crashes (rarely, not more than once a week) on -140mV, but is perfectly stable on -135. The temperature difference is negligible, if any..
Try reduceing the undervolting and then test on power and on battery if you still get crashes. 

P.S. And by the way Ballanced perpormance profile is better thatn High Performance. I keep mine Ballanced, slider in the middle - Better performance.

Eshanoy167

MrGrudev said:

No its not normal to crash at all, but it makes more sense if it crashes on power, rather that battery. Because on power, the power delivered to the CPU and GPU is much more than on battery. So if the undervolting is too much it might be a problem. 
If you have any crashed, my suggestion is to reduce the undervolt value a little bit. My crashes (rarely, not more than once a week) on -140mV, but is perfectly stable on -135. The temperature difference is negligible, if any..
Try reduceing the undervolting and then test on power and on battery if you still get crashes. 

P.S. And by the way Ballanced perpormance profile is better thatn High Performance. I keep mine Ballanced, slider in the middle - Better performance.

Thanks a lot man for your advice man!
Does anyone have any tips for decreasing temps without making nay hardware changes?
I already have a cooling pad(crappy one) And have undervolted my laptop as far as it can go without crashing, But while playing apex, I constantly hit 90C or more. My coolboost is always on as well.

Valter1Valter

I bought laptop with i7-8750h gtx 1050ti and 16gb RAM. Temperature goes up to 97C while playing. So i have few questions for you guys if would be kind to answer.
1. Does anyone have complete guide how to udnervolt i7-8750h so temperatures can drop but performance can drop only a little (I know that i have to drop cores from 3.9 to around 3.5 but I've never done undervolting). So if someone has pictures or video how to do it I would be thankful
2. Does cooling pad help with temperature. And do I get one with small fans or large ones.

MrGrudev

MrGrudev said:

1.First set your Windows power plan to Ballanced. (minimum processor state 0% ; maximum processor state 100%) and put the slider in the middle - Better performance
2. Throttlestop 
The options are up to you if you want to have the temperatures in the system tray, if you want to have battery profile or not as so on..... You can leave it without changing anyhing.
I set 2 plans in the throttestop called Performance and Game.
In the Performance plan maximum turbo limits are 41,41,40,40,39,39 as it is the maximum you can get from your CPU.
Second plan (Game) I reduced the maximum turbo limits on all 6 cores to 3.4Ghz. This is fine for most of the games since they dont use your CPU at 100%, but if you leave it at 3.9 will increases temperatures. If you are not willing to sacrefice a little performance then go with the 1st plan.
Both plans are undervolted by -135.7mV for CPU Cache and CPU Core. Igpu is undervolted by -50.8mV (Thats not so important because when you are gaming or whatever you are doing to load your notebook you are using the Nvidia)
My forth plan is Battery where the undervolt is same but I disabled turbo. You can do this by either click on the disable turbo checkbox or in the FIVR Turbo ration limits 22 for all cores. That helps increasing the battery life a lot. Maybe double it.
TDP is left default, because you cannot change the TDP for this notebook yet. Maybe soon Acer will release update where this feature will be unlocked, as they do for other Predator notebooks.
Your CPU may be unstable at -135mv undervolt or may be stable at even higher values. Best start with lower value, lets say -110mV, test few days and if you dont get Blue Screens and game crashed increase further until you get a blue screen. Then reduce the undervolt with -5mv and you should be OK.
Remember to save or apply after every change you make in throttlestop.
If you have any questions feel free to ask

Valter1Valter

does set multiplier have to be up to 61t.
does BD PROCHOT have to be checked ?
and speed shift epp.... some people lower it to 0.

MrGrudev

Multiplier is unchecked. I believe on this generation of CPUs, multiplier doesn’t work. Leave it unchecked.
Sheepshift is a tricky. You have to find your ballance. On 255 (which is maximum) your cores will tend to stay as lower as possible. But when you need mor performance (gaming) it takes time to increase the frequency, which leads to lags sometimes and decreased performance of the CPU. If you put it on 0 (minimum) your cores will be always “ready” at max frequency, but will produce more heat. Just start the game you play and test. Put it in the middle, about 120 and check if that is enough to run it smoothly. If not decrease a little bit.
BD prochot leave it ON.
About the question you asked me in private message for the turbo ratio - it depends. If you play very CPU demanding games leave it at maximum, but for most of the games you dont need so much of a CPU. To be honest disabling turbo (max turbo ratio limit set to 28 or checking the disable turbo check box) is enough for a lot of games. Again check it by playing and changing the settings.