How to interpet PL1 and various other limits, I7 8750h ?

Discussion in 'Hardware Components and Aftermarket Upgrades' started by Mick911, Apr 30, 2019.

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  1. Mick911

    Mick911 Newbie

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    Hey, could somebody kind enough please help me to understand why im running into PL1 and including many other limits with following settings on my I7 8750h in Throttlestop? Note that turbo is set on 3.6mhz which seems low for this processor, when its set anywhere from 3.7-3.9 it will start throttling even more frequently throwing more limit reasons. CPU temps go barely past 85c while under load.
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    Any help is much appreciated
     
  2. unclewebb

    unclewebb ThrottleStop Author

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    The Turbo Boost Long Power Max setting in the TPL window is what controls PL1 throttling. You have this set to 45 Watts. If increasing this does not eliminate PL1 throttling then try enabling the FIVR - Disable and Lock Turbo Power Limits option. This trick works wonderful on the TONGFANG based laptops but might not do anything on other name brand laptops from manufacturers like Asus and Dell. It does not hurt to try this. Cinebench can hit 1300+ on TONGFANG laptops with the 8750H.

    Some 8750H owners have had success by using a larger undervolt on the CPU core. -250 mV core and -125 mV cache might be OK. Go up in small steps on the core while a benchmark is running to see if it helps the CPU run faster.

    The default Turbo Ratio Limits for the 8750H from top to bottom in the FIVR window are 41, 41, 40, 40, 39, 39. Increasing any of these values higher than default will not accomplish anything. Going lower is OK.

    There is a huge thread dedicated to ThrottleStop questions. The link is in my signature.
     
    Valour549, bennyg, Papusan and 2 others like this.
  3. Mick911

    Mick911 Newbie

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    Thanks alot for your reply! -250 mv core and -125mv cache works like charm. I didnt change the Watts yet because not very sure yet how to adjust the values but i also noticed that package power hits 67W during Cinebench sessions, after minute or so running it starts to throttle and when throttling then package power sits around 45W. Since its hitting 67W during benching can be that power max settings in TPL window is already overrun by bios settings? Also i tried "Disable and Lock Turbo Power Limits option". Still getting PL1 throttle during benching although max CPU temp 85c, struggle is real
     
  4. bennyg

    bennyg Notebook Virtuoso

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    TL;DR... yes. If you set short turbo (PL1) and long power (PL2) higher, and they're not instantly changed and let your cpu run beyond the old values to either maximum multipler or thermal throttle, the values are locked.

    The CPU runs turbo (PL2) watt power limit for (turbo timer) seconds before reverting back to base (PL1) power limit, until idle resets the turbo timer. That is what is occurring with the 67W/45W behaviour.

    Change PL2 and turbo timer to as high as they'll go is the way to permaturbo any locked cpu up to their maximum multipliers... if BIOS/firmware allows.
     
  5. 4W4K3

    4W4K3 Notebook Evangelist

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    I'm curious if other processors can benefit from a 'staggered' undervolt like this? I have a 7300HQ that doesn't like anything below -0.1055v core/cache and I've read countless times that the values of core and cache need to match. If this isn't the case; I have a lot more testing to do.
     
  6. Raidriar

    Raidriar ლ(ಠ益ಠლ)

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    I run -200mV core -160mV cache on my 7700HQ
     
  7. 4W4K3

    4W4K3 Notebook Evangelist

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    That's really good. My laptop won't come anywhere near those levels. Even -0.135v core and -0.105v cache was too much for the 7300HQ coming out of a cold boot. I've found it can run hours (even overnight) on load, but it can still very easily crash coming out of idle or weird things like that. At least, that's how my particular machine is.
     
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