OC'ing i5 8600k - why are my temps so high?

Ali3ta1r · 31 Aug 2018 at 09:38

Hey guys,

So I'm a first time OC'er and have a pretty decent rig which I use purely for gaming, I have been following some basic guides online to increase my i5-8600K from it's factory 3.60Ghz. My specs are as follows:

Case: Phanteks Enthoo
MOBO: Gigabyte Z370 AORUS Gaming 7
GPU: Palit GeForce GTX 1080 GameRock 8GB
CPU: Intel i5-8600K
Cooler: Noctua NF-A14
PSU: Seasonic Focus Plus 650 W Gold 80
Ram G.SKILL 16GB (2x 8GB) DDR4 3200MHz CL16 Trident Z RGB

So my current changes which I made to the BIOS are as follows:

1. Load "Profile1" on X.M.P
2. Changed my CPU Clock Ratio to 45
3. Disabled VT-d & Internal Graphics
*left Intel Speed Shift Technology and CPU Enhanced Halt plus C3, C6/C7, C8 & C10 State Support on Auto*
4. "Uncore Ratio" left to Auto (think it's 40 by default)
5. Left "Vcore" as Auto
6. Left "Vcore Loadline Calibration" to Auto

I then downloaded CPU-Z, Coretemp and Prime95. This is where my concerns begin with my temperature, and it seems high (even at idle) and then worsens to a very quick 80C+ within 2 minutes of running a "SmallFFTs" stability test on Prime95.

Is there something glaringly obvious I am missing? Or am I being too ambitious trying to OC to 4.5Ghz with my air-cooling? Any advice on where I should begin to solve this would be appreciated.

Ali3ta1r · 31 Aug 2018 at 11:06

To get me started, where would be a good starting value for Vcore to OC @ 4.5Ghz with above rig?

Also, am I being under ambitious? Would I notice much improvement in my gaming with an extra 0.2 - 0.4Ghz?

Ali3ta1r · 31 Aug 2018 at 11:17

Also, what figure should "Vcore Loadline Calibration" be assigned too?

Ali3ta1r · 31 Aug 2018 at 11:47

mattyfez said:
I'd set vcore to 1.4v and then keep increasing the CPU speed until you get crashes or starts failing tests.
The dial the CPU speed back a notch..

Once happy you can either leave it if temps are ok, or try to dial the vcore down a bit to lower the temperature.

Obviously keep an eye on the temperature..
Cinebech is quicker to run so I'd maybe use that initially as you'll be rebooting a lot and adjusting the CPU speed..
I'd also use HWmonitor as that will display the max temperature reached..

Load line calibration is to combat votalge drops under load (instability) you can leave that on auto for now and use it to fine tune later of needed..
That's also where HWmonitor is useful as even though you've set the CPU to a fixed voltage you'll see it still fluctuates a bit when the CPU is under load .. If it fluctuates too much you can use LLC to minimise that fluctuation.

That seems incredibly high.

Wouldn't 1.4V have my idle temperatures sky high and toast my rig, reducing it's life-span considerably?

I was under the impression anything over 1.28V isn't desirable? Plus, I'm only looking to get to a modest 4.5Ghz.