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i7 8700k won't overclock past 4.5GHz

Discussion in 'CPUs' started by Graptik, 28 Jul 2018.

  1. Graptik

    Associate

    Joined: 15 Jul 2018

    Posts: 14

    Hi, I recently bought an i7 8700k and am trying to overclock it to at least 4.7GHz. Unfortunately I can not get it stable at anything past 4.5GHz even at 1.4v. This is using fixed voltage. I am using OCCT to test stability and so far I have only got to 4.5GHz using 1.3v. Another thing I've noticed is that even when using the highest LLC level available, the voltage under load still drops around 0.3v below what I set in the BIOS. Temps are very good even when using 1.4v. Any help at all would be greatly appreciated.
    Specs:
    CPU:i7 8700k
    Motherboard: ASRock Z370 Pro 4
    GPU: Nvidia GTX 1080ti Founders Edition
    RAM: 2 x 8GB Corsair Vengeance LPX 3000MHz
    Cooler: Corsair H75 AIO
    Storage: 2 x 1TB
    Power Supply: EVGA 600w 80 Plus White
     
    Last edited: 28 Jul 2018
  2. tamzzy

    Capodecina

    Joined: 26 May 2012

    Posts: 12,306

     
  3. Graptik

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    Joined: 15 Jul 2018

    Posts: 14

    If you look at his guide on overclocking the 8700k, the ASRock Pro4 is shown in comparison to other boards and it shown in the guide as being able to hit 5GHz.
     
  4. tamzzy

    Capodecina

    Joined: 26 May 2012

    Posts: 12,306

    sorry, should be more specific, the statement at 10:35 and beyond.
    also you're using an aio cooler = no air to the VRMs, i'd be wary running those kinds of voltages as the VRMs likely wouldn't cope and thermal throttle.
    1.3v should see the cpu at 4.7-4.8ghz on all cores, unless you've lost the #siliconlottery
     
  5. chrcoluk

    Soldato

    Joined: 27 Feb 2015

    Posts: 5,386

    given my recent experience on the 3rd and 4th dimm slots on my board (a high'ish range board to boot) I was gutted to see his ram test was all only using 2 dimm packs :( never testing the secondary dimm slots.
     
  6. Graptik

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    Joined: 15 Jul 2018

    Posts: 14

    Oh okay now I understand. I am using an AIO but I do have a case fan pointing directly down onto the VRMs. Also, as I mentioned in my original post the voltage always seems to be 0.2 - 0.3v under what is set in the BIOS, so 1.3v in the BIOS will in reality be about 1.27v which I wouldn't think would be enough to throttle the VRMs? Also I have been using the correct LLC - Level 1 (opposite to most boards I know).
     
  7. chrcoluk

    Soldato

    Joined: 27 Feb 2015

    Posts: 5,386

    try disabling HTT, so less stress on everything just for the purpose of testing to see if you can get higher than 4.5.
     
  8. LuckyBenski

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    Joined: 28 Dec 2017

    Posts: 4,823

    Location: London

    That's 0.02-0.03V or 20-30mV.

    Are you using HWMonitor to track the voltages?
     
  9. Graptik

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    Joined: 15 Jul 2018

    Posts: 14

    Yes sorry I meant 0.02-0.03v. Yes I am using both HWMonitor and CPU-Z to check voltages. Obviously not both at the same time but they both show the same result.
     
  10. 8 Pack

    OcUK Staff

    Joined: 20 Feb 2012

    Posts: 10,004

    Location: John Smiths Stadium

    Occt ?? Use real bench or some real world test. Do you play occt??

    I don't use this junk but I am sure later versions are avx enabled which again is torturing the cpu.

    An easy way to get more if your just gaming is disable HT. Often infact improves games.
     
  11. Graptik

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    Joined: 15 Jul 2018

    Posts: 14

    It also crashes in regular gaming use at anything more than 4.5GHz so it is not stable at all. 4.5GHz is rock solid at 1.3v (more like 1.27 after the voltage drop).
     
  12. mikeo

    Mobster

    Joined: 17 Aug 2005

    Posts: 2,605

    Location: Scotlandshire

    Not sure what board you've got. But out of interest, have you tried enabling MCE (Multi Core Enhancement) in the BIOS? I'd be interested to hear what voltage it tries to give the CPU to run all cores at 4.7.
     
  13. ToastedChip

    Gangster

    Joined: 11 Jun 2013

    Posts: 155

    odd.. an 8700k should hit 4.7 without any overclocking whatsoever. had mine a few week and its stable @ 5ghz 1.35v and hits 70-76c under load after 30mins, not tried it any further as yet. Im running it at 4.8 all cores with an offset of -60ma, idles 30c and hits 70c under load. Gaming is usually around 40-50c. Motherboard is Asrock z370 extreme4, cooler h115i, GTX 1080, 2xSSD's and 6 x 6tb hdds all mounted with the hdd trays ( had to order extra from coolermaster, cant believer they ship this case with just 2!! ), PSU Silverstone 1000w. Cosmos c700p case with 3x140mm corsair ML fans front ( intake ) - 1 x ML fan rear ( exhaust ) and ive replaced the fans on the rad with 2xMLs. Rad is top mounted with fans pulling through the rad ( easyre cleaning ).
     
  14. mikeo

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    Joined: 17 Aug 2005

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    Location: Scotlandshire

    Not all I7-8700K's will run fully stable at 4.7 all cores at stock. Mine will if the BIOS sets a Vcore core of 1.2 which it usually does. But sometimes at boot, it sets it just below this and this isn't stable. So to mitigate this, I set MCE on and this gives it between 1.2 and 1.25 depending on what's running. Hence my question to the OP regarding MCE. While I have played around with manual voltages (mine takes 1.4 to be stable at 5.0) I'm happy with 4.7 day to day. Classic case of not all CPU's are made equal, so to speak.
     
  15. ToastedChip

    Gangster

    Joined: 11 Jun 2013

    Posts: 155

    i must have got a great chip then because mine will boot and be stable @5ghz 1.35v ( or offset +50ma which gives it around 3.8 under load ). happy with it running -60ma offset all cores 4.8 which hangs around 1.3v. great chip.
     
  16. LuckyBenski

    Mobster

    Joined: 28 Dec 2017

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    Location: London

    I'm really confused, do you mean mV not mA?
     
  17. mikeo

    Mobster

    Joined: 17 Aug 2005

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    Location: Scotlandshire

    That's why they call it the silicon lottery.

    Though 1.35v for 5GHz appears to be the average to reach this. Some will manage it with a bit less, some (like mine) require a bit more.

    PS. He means mV.
     
  18. chrcoluk

    Soldato

    Joined: 27 Feb 2015

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    to be stable at 5ghz and I mean proper stable not game stable, I need 1.38v on my 8600k.
     
  19. ClownsBlur_

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    Joined: 4 Aug 2018

    Posts: 19

    Location: England

    If it helps, I'm 4.7GHz @ 1.26v but I haven't finished testing yet so I will test mine for stability at 1.25v then lower etc. My LLC is set to Turbo also if you wanted to know - it's recommended apparently for a high overclock.
     
  20. imginy

    Mobster

    Joined: 13 Aug 2012

    Posts: 4,087

    Something doesn't sound right they turbo up to 4.7 at stock.

    I would update your bios.

    Maybe it could be a ram issue try running that at stock.