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Help undervolting i7 9750h throttlestop

GioB18

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Hi everyone,
This cpu fitted in my workstation (lenovo p53) generates a lot of heat. The laptop runs frequently under full load for hours, in this situation cpu temperatures never fall below 95°C and full speed fans makes no difference. Downloaded throttlestop and started to play with it but i'm struggling with it.
System automatically shuts down @-200mV on CPU and/or -180mV on cache. Aida64 still notice throttling @ -160/140mV. Moreover when undervolted the laptop seems more "lazy" compared to the OEM configuration.
I tested the undervolt with some numerical simulation i'm working with while monitoring Limit Reasons window. Well:
-thermal throttle still happens
-quite often cpu is being power limited but actual power consumption in 20W while the short term PL is set by default to 60 and PL2 to 90
-VR CURRENT limit appears
-i see no gain in performance (same analysis time)
Am i doing something wrong? My questions are
-what is that vr current limit
-is it safe to increase power limits letting thermal throttle do the job if needed
-how can i tune the setup to make the cpu safely run at maximum speed for the time is needed limiting any kind of throttling.
I also bought a stick of thermal grizzly to improve the gain from undervolt
 

unclewebb

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Have you enabled the FIVR - Disable and Lock Turbo Power Limits feature yet?

quite often cpu is being power limited but actual power consumption in 20W
If you are seeing VR CURRENT in red, your CPU is throttling because of this voltage regulator limitation. There is no easy way to get around this using ThrottleStop or any other software that I know of. The voltage regulator is not capable of meeting what is being demanded of it. Best to reduce power consumption by lowering the CPU speed to avoid this type of throttling. VR CURRENT throttling can reduce power consumption well below the rated TDP.

Whether your CPU throttles because it is hitting the turbo power limits or thermal limits does not really matter. Throttling is throttling. Either one is going to prevent you from getting maximum and consistent performance out of your CPU. Manufacturers that include these CPUs in their products need to put some more thought into their thermal solutions and more thought into their power designs so the CPU can reach and maintain its full rated speed. It is false advertising when they do not.
 

GioB18

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No, i have not enabled FIVR - Disable and Lock Turbo Power Limits. What does it do?
I'm struggling to understand what you say about vr current, i mean, the difference with power limit limitation.
The reason why i do not see vr current limitatiom before undervolting is because thermal throttling happens before it?

So.. is there something i can do to improve cooling? Liquid metal can be enough?
 
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Cooling just isn't great on the P53, it wasn't great on the P52 either (knew someones who scored worse than a 2018 MBP with fan curve lol).
Just try and get a stable undervolt, and repaste if its not enough. Also try out TPFancontrol
 

GioB18

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TPFanControl..already running it but i would like it had fewer bugs. Sometimes it spins up only the gpu fan while cpu temps are over 90°C, sometimes fans do not kick in at all, sometimes fans remain engaged when temps drop. Yes yes i edited its .ini file but that's the situation. One out of four times it require to manually switch mode to "wake it up"
 

unclewebb

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FIVR - Disable and Lock Turbo Power Limits. What does it do?
Intel CPUs use multiple sets of turbo power limits. This feature disables the secondary set of power limits. This does not help all laptops but I have had success using this feature on several Lenovo laptops.

In examples I have seen, VR CURRENT throttling seems to be much more severe compared to thermal or power limit throttling. In other words, I would do whatever possible to avoid VR CURRENT throttling. Make adjustments to CPU speed or power consumption so you never see VR CURRENT lighting up in red.

Your laptop is living on the edge of throttling. You can make lots of adjustments and try to get a little more out of it but ultimately you are running up into 3 different brick walls at the same time. If you overcome power limit throttling, you will probably run into thermal throttling or your laptop will not be able to supply enough current to the CPU so you will get current limit throttling instead.

No matter what you do, your CPU is probably not going to be able to run indefinitely at its full rated speed. Many laptops are in the same boat.

The laptop runs frequently under full load for hours
I usually do not recommend any Dell laptops but something like the Alienware Area 51m might be better suited to this kind of load. It uses desktop processors in a laptop configuration. Dell put some thought into including adequate cooling.

 
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Downloaded throttlestop and started to play with it but i'm struggling with it.
But what's the point?
Throttling is not a problem. It's a smart function of modern CPUs that makes them run in near optimal, sustainable way.
Throttling applies temporary frequency limits.

For some weird reason you're trying to prevent this by applying constant adjustments, which may lower performance or compromise stability.

If your goal is to get as much performance as possible (i.e. complete a simulation in shortest possible time), don't mess around. Let the CPU decide for itself. It's almost impossible for you to do better.

If your goal is something else: lower temps, stable clocks etc - keep in mind that undervolting can cause computation errors.
In games that means artifacts (which one can live with). In computing it means incorrect results.
 

woodpecker

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From my experiments on a MSI Prestige 15 with i7-10710u the built in throttling is not very well optmisied for tasks that require long term 100% cpu loads, what I've found works best is to limit PL1 to a value that stops or almost stops throttling, also reduce PL2 to just above PL1 and clamp them. Set the turbo time limit to a couple of seconds. When running 100% cpu load for long periods it makes no sense to run above the max power limit the platform can maintain, if it does throttle there is no point in coming out of the throttle up to a massive PL2 of 60W/90W etc for 28 seconds as you'll probably hit the throttle again before it settles back to PL1, you can get a much better average by tweaking than allowing the platform to bounce up and down on the throttle stops.

From testing on my Prestige 15 with default PL1 45W and PL2 52W it will bounce between 1.1GHz and 3.7Ghz when it throttles resulting in an R20 looping benchmark dropping to about 2100-2200. If I set PL1 to 37W and PL2 to 40W undervolt -125mV with a turbo time limit of 2 seconds looping R20 will average 2500-2600 which is way better than the built in throttling. This does only apply to applications that require long term 100% cpu loads, the built in limits do quite well on shortish bursts, from cold with built in limits it will hit 2850 in R20 but only on the first run, YMMV.
 

gutsee

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Have you enabled the FIVR - Disable and Lock Turbo Power Limits feature yet?


If you are seeing VR CURRENT in red, your CPU is throttling because of this voltage regulator limitation. There is no easy way to get around this using ThrottleStop or any other software that I know of. The voltage regulator is not capable of meeting what is being demanded of it. Best to reduce power consumption by lowering the CPU speed to avoid this type of throttling. VR CURRENT throttling can reduce power consumption well below the rated TDP.

Whether your CPU throttles because it is hitting the turbo power limits or thermal limits does not really matter. Throttling is throttling. Either one is going to prevent you from getting maximum and consistent performance out of your CPU. Manufacturers that include these CPUs in their products need to put some more thought into their thermal solutions and more thought into their power designs so the CPU can reach and maintain its full rated speed. It is false advertising when they do not.
Can you explain what does enabling "Disable and Lock Turbo Power Limits" feature does?
Thanks!
 

unclewebb

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There are a duplicate set of turbo power limits within Intel CPUs. The Disable and Lock feature does exactly that. It disables and locks the secondary set of turbo power limits. This prevents Windows or any other software from adjusting these. This feature has helped overcome many throttling schemes.

There is also a third set of turbo power limits. There is no free software available to get beyond this third set of limits. Some manufacturers like Dell and HP are using this third set but many laptops are not yet using these limits.
 
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