i7 8700k 4,7Ghz MAX Turbo Limit

Hi guys,

I have an intel I7 8700K mounted on ASUS Z370-E Gaming motherboard with a Cooler Master MasterLiquid 240 Pro AIO cooler. I tried running 4.7Ghz on all cores. I set my VCORE to Adaptive mode and a value of 1.2 V, Load Line Calibration to 4 (with 3 it fails in Prime95 10 sec into the test). I maxed out the power and current limits. Now when i run Prime95 Small FFT test, i get 4,7Ghz at first, but it drops to 4,6 and remains there, with the test running stable. Looking in HWiNFO i see "IA: Max Turbo Limit" set to YES. There are no other events (no throttling due to temperatures or power draw). The CPU temperature never goes over 79 degrees during the prime95 test. What could be causing the CPU to throttle down to 4,6Ghz? I attached a screenshot from HWiNFO.

Reply to nightmare392
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More about 8700k 7ghz max turbo limit
  1. Is prime running on all cores?

    A 8700k with boost will run at these speeds per core used

    1 core 4.7
    2 core 4.6
    3 core 4.5
    4-5 core 4.4
    6 core 4.3

    So if prime for some reason is only using 2 cores then it cpu would default to 4.6 ghz on boost
    Reply to faalin
  2. Max Turbo Limit - is telling you just that you've reached what you have set as turbo limit.

    What version of prime?

    Do you have an AVX offset set?
    Reply to biglizard
  3. My prime95 version is 29.4. I have AVX offset set to 0. I set the limit on all cores to 47, and they all go to 47 for the first 20-30 seconds, dropping to 46 after that. prime95 is running on all cores
    Reply to nightmare392
  4. nightmare392 said:
    My prime95 version is 29.4. I have AVX offset set to 0. I set the limit on all cores to 47, and they all go to 47 for the first 20-30 seconds, dropping to 46 after that. prime95 is running on all cores


    You have said you set vcore to 1.2, your showing 1.152 in hwinfo.

    I'm curious if setting LLC to 5 would make a difference. Too much droop?

    How long did you run prime for?

    Run Version 26.6, see if same behavior.
    Reply to biglizard
  5. My vcore is set to 1.2 adaptive, not fixed. I will try to set LLC to 5, but it might bring the temperatures up. I ran prime for about an hour. In large fft (512-4096) it does the same.
    Reply to nightmare392
  6. nightmare392 said:
    My vcore is set to 1.2 adaptive, not fixed. I will try to set LLC to 5, but it might bring the temperatures up. I ran prime for about an hour.


    Any increase in core voltage will increase temps, as you know.

    Seems strange that your losing a bin with no power or temp reasons.
    Reply to biglizard
  7. That is what i can't understand. There is no reason to throttle. Temps are good, power limit is not reached, vrm is not too hot to cause throttling. Maybe it's not getting enough vcore. Should i try to increase to 1.25V and see if it can hold 4,7? It seems a bit too much 1.25V for 4.7Ghz.
    Reply to nightmare392
  8. nightmare392 said:
    That is what i can't understand. There is no reason to throttle. Temps are good, power limit is not reached, vrm is not too hot to cause throttling. Maybe it's not getting enough vcore. Should i try to increase to 1.25V and see if it can hold 4,7? It seems a bit too much 1.25V for 4.7Ghz.


    I'd try upping LLC first.

    Low voltage is my thinking also. Since your using Prime ver 29 which use AVX instructions, it may be dropping a bin. Normally this would just be unstable, though.

    Have you set AC/DC load lines to 0.01?

    How do you know that VRM is not hot? I wouldn't think that they are considering vcore, Just curious.
    Reply to biglizard
  9. The AC/DC load lines are set to 0.01. Leaving them on Auto was causing VR Thermal Alert and throttling (the motherboard was probably setting a very high value). I will try upping LLC tomorrow, when i get back from work. If it doesn't work, i will try to increase Vcore. In the mean time, i had to increase VCCSA to 1.3 and VCCIO to 1.25 to get my G.Skill 3200Mhz memory to work with XMP enabled (i gradually raised the values from 1.1 and 1.15, until i got no fail in Prime95 512k-4096K). The values seem high, but i could not get it stable with anything under these. The DRAM voltage is set to 1.35 by the XMP. I tried 1.36 with VCCIO and VCCSA to 1.15 and 1.2 and it would fail in Prime95. It has been running for 2h now without errors, but i am worried that the 1.3V VCCSA might be a little high.
    Reply to nightmare392
  10. nightmare392 said:
    The AC/DC load lines are set to 0.01. Leaving them on Auto was causing VR Thermal Alert and throttling (the motherboard was probably setting a very high value). I will try upping LLC tomorrow, when i get back from work. If it doesn't work, i will try to increase Vcore. In the mean time, i had to increase VCCSA to 1.3 and VCCIO to 1.25 to get my G.Skill 3200Mhz memory to work with XMP enabled (i gradually raised the values from 1.1 and 1.15, until i got no fail in Prime95 512k-4096K). The values seem high, but i could not get it stable with anything under these. The DRAM voltage is set to 1.35 by the XMP. I tried 1.36 with VCCIO and VCCSA to 1.15 and 1.2 and it would fail in Prime95. It has been running for 2h now without errors, but i am worried that the 1.3V VCCSA might be a little high.


    It is somewhat high for 3200mhz, but if I'm not mistaken higher SA can be needed to stabilize a weak IMC. Higher LLC may raise IO and SA it does on my board. You may want to compensate for that.
    Reply to biglizard
  11. Is there any way that something else is affecting the stability of the RAM, and raising VCCSA is compensating? Nothing comes to my mind, but maybe i'm missing something
    Reply to nightmare392
  12. nightmare392 said:
    Is there any way that something else is affecting the stability of the RAM, and raising VCCSA is compensating? Nothing comes to my mind, but maybe i'm missing something


    With SA too high can cause instability, its the touchiest of all the voltages in my experience.

    According to this write up, your on the high side but ok. http://edgeup.asus.com/2017/kaby-lake-overclocking-guide/3/
    Reply to biglizard
  13. I found the problem with the multiplier dropping to 46. I had Intel Extreme Tuning Utility installed and it had 46 set (i must have set it at some time). Now it goes to 4.7, but i have other problems. I set 1.2V in the BIOS, and i get 1,152 during full load in Prime95. If i increase LLC to 6 i get VR Thermal Alert (the VRM is probably too hot). Should it be getting so hot at only 1.2V Vcore, and why the huge voltage drop? Am i doing something wrong? I also tried setting 1,225V, and i was getting 1,120V during load, with LLC set to 5.
    Reply to nightmare392
  14. nightmare392 said:
    Hi guys,

    I have an intel I7 8700K mounted on ASUS Z370-E Gaming motherboard with a Cooler Master MasterLiquid 240 Pro AIO cooler. I tried running 4.7Ghz on all cores. I set my VCORE to Adaptive mode and a value of 1.2 V, Load Line Calibration to 4 (with 3 it fails in Prime95 10 sec into the test). I maxed out the power and current limits. Now when i run Prime95 Small FFT test, i get 4,7Ghz at first, but it drops to 4,6 and remains there, with the test running stable. Looking in HWiNFO i see "IA: Max Turbo Limit" set to YES. There are no other events (no throttling due to temperatures or power draw). The CPU temperature never goes over 79 degrees during the prime95 test. What could be causing the CPU to throttle down to 4,6Ghz? I attached a screenshot from HWiNFO.




    nightmare392 said:
    I found the problem with the multiplier dropping to 46. I had Intel Extreme Tuning Utility installed and it had 46 set (i must have set it at some time). Now it goes to 4.7, but i have other problems. I set 1.2V in the BIOS, and i get 1,152 during full load in Prime95. If i increase LLC to 6 i get VR Thermal Alert (the VRM is probably too hot). Should it be getting so hot at only 1.2V Vcore, and why the huge voltage drop? Am i doing something wrong? I also tried setting 1,225V, and i was getting 1,120V during load, with LLC set to 5.


    Try more air flow over VRM.

    Are VRM heat sinks fastened tightly?

    If those don't help, I'd RMA or return board.
    Reply to biglizard
  15. I tightned the vrm heatsink screws a bit and i got the termal alert later. It seems like setting ac/dc load lines both to 0.01 causes the huge difference between the set vcore and the actual one. I reverted back to stock, but with the load lines on auto i get 83-84 degrees at 4.3Ghz. Something is not right. I should't be getting these temps with an 240mm AIO cooler.
    Reply to nightmare392
  16. nightmare392 said:
    I tightned the vrm heatsink screws a bit and i got the termal alert later. It seems like setting ac/dc load lines both to 0.01 causes the huge difference between the set vcore and the actual one. I reverted back to stock, but with the load lines on auto i get 83-84 degrees at 4.3Ghz. Something is not right. I should't be getting these temps with an 240mm AIO cooler.


    Temperature has everything to do with any CPUs performance and just how fast the CPUs temperature is approaching higher numbers depends on how much the CPU throttles itself to protect itself and those protective features are built into the CPU. The first protection features are sent by the CPU to the motherboard to tell the motherboard to increase the CPU fan speed but if the response is not fast enough the CPU activates internal protective features. These protective features may not even show up as drastic as the multiplier dropping, but are measurable in a benchmark when you suddenly see your previous scores dropping.

    That said I would like to help you reach a higher overclock, with the cooling you are running you should at least be able to run 4.7ghz on all cores. I am running an 8700K with all cores overclocked to 5ghz at 1.325v, however to reach that I am running chilled water cooling and the CPU has been delided, but I was running 5ghz before I delided the CPU and the delid has allowed running a lower Vcore and lower temperatures.

    Are you willing to run a manual Vcore, and how many levels of LLC does your motherboard BIOS have? I am running the ASUS ROG Maximus X Hero and we need to compare some notes BIOS wise between it and your ASUS Z370-E Gaming?
    Reply to 4Ryan6
  17. One more thing, are you running the last available BIOS Flash for your motherboard, if not you need to flash it to the last released BIOS.

    I have other things to get done today but I'll check back when I can. Ryan
    Reply to 4Ryan6
  18. Thank you for your answer. I know that temperature has everything to do with the performance of the CPU, but i am getting too high temperatures for an AIO cooler at stock frequencies (i have the CoolerMaster MasterLiquid 240 Pro). I have the latest BIOS (0606). My BIOS has 7 levels of LLC, but the max i could reach is 5 before my VRM begins to throttle. Something doesn't seem right. At stock (4.3 Ghz on all cores) i get a power draw of 141W (it seems a little high for stock). On Auto Vcore i get 1.232V with all cores at 4.3Ghz during Prime95 small fft test. I attached a screenshot from HWinfo, that shows temperatures when running prime95 small fft, and the power draw. I will try to remove the cooler and the CPU, look for any bent pins on the socket and install everything back applying thermal paste again (i am using Gelid GC-Extreme paste). I hope i don't have a deffective CPU that draws too much current. Since you have offered to help, any advice is welcome. Thank you!
    Reply to nightmare392
  19. The red flag I see in your last HWiNFO is under your CPU Package Power 141.8w and for the clock on a 95w TDP CPU that's way too high, mine is no where near that high at a 5ghz OC, right off the bat I would say somethings wrong with your motherboard.
    Reply to 4Ryan6
  20. That power draw is under full load (prime95 small fft). How much power draw do you have while running prime95? If my motherboard is bad, i will send it back to get replaced. I am also worried about the fact that when my CPU is hot (80-90) degrees, the aio radiator is just a little warm, not hot. The pump is working at 100% rpm (the bios shows 9000 rpm, but it is probably 3000).
    Reply to nightmare392
  21. nightmare392 said:
    That power draw is under full load (prime95 small fft). How much power draw do you have while running prime95? If my motherboard is bad, i will send it back to get replaced. I am also worried about the fact that when my CPU is hot (80-90) degrees, the aio radiator is just a little warm, not hot. The pump is working at 100% rpm (the bios shows 9000 rpm, but it is probably 3000).


    My wattage readings running P95 26.6 Small FFTs will not be comparative to yours all my C-states are disabled and I am running coolant temperatures that are 10c below ambient, while your temperatures are constantly above ambient which means even at a 5ghz CPU overclock I am running less wattage than you are, a lot less wattage. But just looking at your wattage #s they are recording way too high 141w on a 95w TDP CPU? Somethings wrong there and it's probably the motherboard.
    Reply to 4Ryan6
  22. 4Ryan6 said:
    nightmare392 said:
    That power draw is under full load (prime95 small fft). How much power draw do you have while running prime95? If my motherboard is bad, i will send it back to get replaced. I am also worried about the fact that when my CPU is hot (80-90) degrees, the aio radiator is just a little warm, not hot. The pump is working at 100% rpm (the bios shows 9000 rpm, but it is probably 3000).


    My wattage readings running P95 26.6 Small FFTs will not be comparative to yours all my C-states are disabled and I am running coolant temperatures that are 10c below ambient, while your temperatures are constantly above ambient which means even at a 5ghz CPU overclock I am running less wattage than you are, a lot less wattage. But just looking at your wattage #s they are recording way too high 141w on a 95w TDP CPU? Somethings wrong there and it's probably the motherboard.



    I think there is something wrong with my AIO also, because i shouldn't be getting 85 C during prime (with AVX) with the stock turbo frequency of 4.3Ghz. I replaced the paste 3 times, so it's probably ok. I'm thinking that maybe the water block does not seat properly on the CPU (maybe the screws are too long on the intel mounting bracket). I'm thinking of going for a Corsair H115i instead of the CoolerMaster MasterLiquid 240 Pro i have at the moment. Wold it be a better choice? I also have the power limis to the max, so it never power throttles, that is probably why i get to 141W power draw, and because i am using prime95 with AVX, not 26.6. I tried 26.6 now and i get 107 W power draw and max 73 C.
    Reply to nightmare392
  23. nightmare392 said:
    I tried 26.6 now and i get 107 W power draw and max 73 C.


    That's looking more realistic!

    That's closer to my #s at a 5ghz OC, but still too high for stock.
    Reply to 4Ryan6
  24. 4Ryan6 said:
    nightmare392 said:
    I tried 26.6 now and i get 107 W power draw and max 73 C.


    That's looking more realistic!

    That's closer to my #s at a 5ghz OC, but still too high for stock.



    I ordered a Corsair H115i a few minutes ago. I will pick it up tomorrow and see if i get better temps. After i solve the cooling problem, i will test more OC settings to see if the MB is faulty.
    Reply to nightmare392
  25. nightmare392 said:
    I ordered a Corsair H115i a few minutes ago. I will pick it up tomorrow and see if i get better temps. After i solve the cooling problem, i will test more OC settings to see if the MB is faulty.


    Reviews of that cooler are not very promising, I hope you get a good one.
    Reply to 4Ryan6
  26. 4Ryan6 said:
    nightmare392 said:
    I ordered a Corsair H115i a few minutes ago. I will pick it up tomorrow and see if i get better temps. After i solve the cooling problem, i will test more OC settings to see if the MB is faulty.


    Reviews of that cooler are not very promising, I hope you get a good one.



    If it is not ok, i can return it within 30 days and get something else. If you had to buy an AIO, what would be your choice?
    Reply to nightmare392
  27. The EK XLC Predator vs 1.1 https://www.amazon.com/EKWB-EK-XLC-Predator-Liquid-Cooling/dp/B014CVMMI0

    Unfortunately there were a few leaks with version 1.0 and EK released vs 1.1 of which I have one on my wifes computer and have had zero problems with. But I guess as high a quality as EK is they refused to accept a black eye from anything they produce and they've pulled all the Predator line to revamp the system.

    https://www.ekwb.com/news/ek-is-announcing-modular-liquid-cooling-products/

    As of yet I haven't seen any of these new systems pop up to be acquired yet but hopefully soon but if I was spending my money on an all in one that would be it because quality wise no other company out there producing AIOs can touch it.

    It's the new Phoenix line.

    https://www.ekwb.com/news/ek-mlc-phoenix/
    Reply to 4Ryan6
  28. 4Ryan6 said:
    The EK XLC Predator vs 1.1 https://www.amazon.com/EKWB-EK-XLC-Predator-Liquid-Cooling/dp/B014CVMMI0

    Unfortunately there were a few leaks with version 1.0 and EK released vs 1.1 of which I have one on my wifes computer and have had zero problems with. But I guess as high a quality as EK is they refused to accept a black eye from anything they produce and they've pulled all the Predator line to revamp the system.

    https://www.ekwb.com/news/ek-is-announcing-modular-liquid-cooling-products/

    As of yet I haven't seen any of these new systems pop up to be acquired yet but hopefully soon but if I was spending my money on an all in one that would be it because quality wise no other company out there producing AIOs can touch it.

    It's the new Phoenix line.

    https://www.ekwb.com/news/ek-mlc-phoenix/


    Unfortunately the EK XLC Predator is out of stock everywhere i checked, and i really need to solve my cooling problem so i can be sure if my MB is bad or not. If it arrives, i will return the h115i and buy the EK XLC Predator.
    Reply to nightmare392
  29. You're probably not going to find the EK XLC Predator even on Ebay, have you even considered a custom loop?

    There are really good starter kits available.

    http://www.performance-pcs.com/raystorm-pro-photon-d5-ax280-watercooling-kit.html#Details

    This kit comes with a D5 pump mounted on the reservoir that can be mounted horizontally or vertically.
    The pump is plenty strong even for expand-ability to a 2nd radiator if needed, or water cooling a graphics card or 2. The radiator is the basically the same size as the Corsair you're considering but thicker and can handle more cooling. The Raystorm CPU water block is a great block as many water coolers can attest to. A kit like this will last you a long time and be transferable when you upgrade later.

    Just a suggestion.
    Reply to 4Ryan6
  30. I am considering a custom loop, but i don't know if any custom loop is going to fit inside my case (NZXT S340 Elite), and for the next few months i don't want to spend too much on any pc related stuff.
    Reply to nightmare392
  31. Understood.
    Reply to 4Ryan6
  32. Later this year, i might decide on a custom loop, and i would like to cool everything with it (cpu, gpu, vrm). I hope it's ok to ask for your advice on what parts are ok to buy. Can that starter kit in your link be expanded to cool the graphics card, and VRM?
    Reply to nightmare392
  33. Yes and Yes
    Reply to 4Ryan6
  34. I have installed the H115i, and the temps are a little lower, but still seem high. I think there is a problem with the TIM between the chip and the heat spreader. I know Intel is famous for using bad quality TIM, but i think i got the worst. I have made a request to Intel and i will wait for a response. The CPU gets to 80C while the water in the cooler slowly rises from 30 C to almost 40 C. It seems like the heat doesn't escape fast enough to get transfered to the cooler. Have you ever seen a CPU with this kind of problem? With prime95 26.6 i get max 72C. Right now everything is stock, including Auto Vcore. I might get lower temps with lower Vcore, but still i think my CPU is getting too hot
    Reply to nightmare392
  35. nightmare392 said:
    I have installed the H115i, and the temps are a little lower, but still seem high. I think there is a problem with the TIM between the chip and the heat spreader. I know Intel is famous for using bad quality TIM, but i think i got the worst. I have made a request to Intel and i will wait for a response. The CPU gets to 80C while the water in the cooler slowly rises from 30 C to almost 40 C. It seems like the heat doesn't escape fast enough to get transfered to the cooler. Have you ever seen a CPU with this kind of problem? With prime95 26.6 i get max 72C. Right now everything is stock, including Auto Vcore. I might get lower temps with lower Vcore, but still i think my CPU is getting too hot


    My temperatures were higher than I wanted that's why I delided my 8700K, I used the Dr. Delid Professional Tool to do it, nice tool, good German engineered quality, and the delid and relid was very easy.

    http://www.aquatuning.us/water-cooling/cpu-water-blocks/cpu-spare-parts-accessories/22198/aquacomputer-dr.-delid-professional-tool-for-skylake-and-kaby-lake-processors?sPartner=googleshoppingusa&gclid=EAIaIQobChMIh6SP87SH2AIVzwQqCh24AAZeEAYYASABEgITGfD_BwE
    Reply to 4Ryan6
  36. I will probably delid. How much did your temps drop after delid?
    Reply to nightmare392
  37. nightmare392 said:
    I will probably delid. How much did your temps drop after delid?


    A minimum of 15c
    Reply to 4Ryan6
  38. I found someone who has a delid tool, so i don't have to buy one and wait for it to arrive. I will delid tomorrow.
    Reply to nightmare392
  39. nightmare392 said:
    I found someone who has a delid tool, so i don't have to buy one and wait for it to arrive. I will delid tomorrow.


    I replaced the TIM under the heat spreader with Cool Laboratory Liquid Metal Pro, and resealed the Heat Spreader to the CPU substrate with Permatex Black Silicone Gasket Maker you can snag the gasket sealer from an auto parts store.

    The most time consuming part of it was removing the old sealer from the heat spreader and the CPU substrate, I strongly suggest if you have no experience to research how others did the delidding. Oh almost forgot there are either 3 or 4 exposed copper contact points I think it's 3 that you'll need to insulate, many use clear nail polish to do it, I used black liquid tape takes a very small amount to seal the copper.

    FYI: If you're not going to use some type of liquid metal to replace the stock Intel TIM you're probably wasting your time, either use Thermal Grizzly Conductonaut, or Cool Laboratory Liquid Ultra or Pro.

    The good thing about me having to wait the 3 weeks to get the tool was giving me research time into how to do it, some have failed not everyone has been successful, do not forget that Please.
    Reply to 4Ryan6
  40. 4Ryan6 said:
    nightmare392 said:
    I found someone who has a delid tool, so i don't have to buy one and wait for it to arrive. I will delid tomorrow.


    I replaced the TIM under the heat spreader with Cool Laboratory Liquid Metal Pro, and resealed the Heat Spreader to the CPU substrate with Permatex Black Silicone Gasket Maker you can snag the gasket sealer from an auto parts store.

    The most time consuming part of it was removing the old sealer from the heat spreader and the CPU substrate, I strongly suggest if you have no experience to research how others did the delidding. Oh almost forgot there are either 3 or 4 exposed copper contact points I think it's 3 that you'll need to insulate, many use clear nail polish to do it, I used black liquid tape takes a very small amount to seal the copper.

    FYI: If you're not going to use some type of liquid metal to replace the stock Intel TIM you're probably wasting your time, either use Thermal Grizzly Conductonaut, or Cool Laboratory Liquid Ultra or Pro.

    The good thing about me having to wait the 3 weeks to get the tool was giving me research time into how to do it, some have failed not everyone has been successful, do not forget that Please.



    I delided and applied Thermal Grizzly Conductonaut. The temps dropped from 81-83 C to 58-60 C at stock in prime95 with AVX. In prime95 26.6 it never goes over 53C. I get 20 C lower temps on average. That is one cold CPU
    Reply to nightmare392
  41. I flashed the latest BIOS (0607) that was released 2 days ago and my XMP seems stable now with 1.2 VCCIO/VCCSA (they are set automatically to these values when i activate the XMP profile. With the old BIOS they were set to 1.3V VCCIO and 1.25 VCCSA). I am now running 4.7Ghz at 1.2V adaptive Vcore with LLC 5, and it is stable. I think this MB has very weak VRM, because it overheats under heavy AVX load (small fft in the latest version of prime95). Under any stress test i get Vcore exactly as it is set, but under prime95 small fft with avx i set 1.2, and it drops to 1.136V. I do not get crashes or errors, but the VRM throttles after 15-20 min. I am probably going to get a MB with a better VRM. Any suggestions for a MB with a solid VRM?
    Reply to nightmare392
  42. ASUS ROG Maximus X Hero
    Reply to 4Ryan6
  43. Thanks! Unfortunately i have bought the parts in november, so it's a little too late to return the board and get the Hero. I will probably end up selling my current MB and than buying the Hero.
    Reply to nightmare392
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