Question 8700k stable at 1.168v 4.7GHz

superfrillz12

Prominent
Jun 15, 2018
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Hi all so i have

8700k, currently ocing to 4.7ghz
asus rog strix z-370-e
16gb rgb 3600mhz ram
500gb 970 evo m.2 nvme ssd
vega 64 nitro+
650w seasonic focus plus gold
h700i
4tb sata hdd

My oc is done through sync core ratio to 47, manually oc ram. Set power limit to max, disabled c states and set voltage to 1.205 with llc of 5. Initially i used llc of 4 but that crashed my machine within 5 minutes of my ffmpeg hd to wqhd script. So i ran llc of 5 and done that test again, voltage was around 1.168, then once that was done i did realbench stress test for 8 hours with 8gb. The data from hwinfo64 are here https://docs.google.com/spreadsheets/d/1w-9p6TzBuUfrg1UZZUOD7kmjk8t0vaEMUNQpYLh_BNc/edit?usp=sharing

The voltage was staying at 1.168v and not going up to 1.205v as set in the BIOS.

Am i fine with staying with this llc?
 

Darkbreeze

Titan
Moderator
If it passes 8 hours of Realbench, then it's pretty damn stable. If you want to further ensure stability you might do an 8 hour run of this but normally any stability issues show up within 8 hours running Realbench. Might also run it with the full 16GB just to see how it does in Realbench with full memory allocation.

The procedure below is primarily for testing memory configurations, but it will usually quickly pick up any instability issues from CPU configurations as well.

Final testing with Prime95

It is highly advisable that you do a final test using Prime95 version 26.6 (And ONLY version 26.6 except as noted below) choosing the Custom test. You can also use the Blend mode option but after a fair amount of personal testing, asking questions from some long time members with engineering level degrees that have forgotten more about memory architectures than you or I will ever know, and gathering opinions from a wide array of memory enthusiasts around the web, I'm pretty confident that the custom option is a lot more likely to find errors with the memory configuration, and faster, if there are any to be found.

Please note as this is rather important, if you prefer, or have problems running version 26.6 because you have a newer platform that doesn't want to play nice with version 26.6, you can use the latest version of Prime95 with the Custom test selected but you will need to make the following change.

If you wish to use a newer version than 26.6 make the following edit to the "local.txt" file located in the Prime95 folder.

Find the line value that specifies CpuSupportsAVX=1, and change it to CpuSupportsAVX=0

Then click File-->Save, and then close the document.

Now open Prime95.

Click on "Custom". Input a value of 512k in the minimum FFT size field. Leave the maximum FFT size field at 4096k. In the "Memory to use" field you should take a look at your current memory allocation in either HWinfo or system resource monitor. Whatever "free" memory is available, input approximately 75% of that amount. So if you currently have 16GB of installed memory, and approximately 3GB are in use or reserved leaving somewhere in the neighborhood of 13GB free, then enter something close to 75% of that amount.

So if you have 13GB free, or something reasonably close to that, then 75% of THAT would be 9.75GB, which, when multiplies times 1024 will roughly equal about 9984MB. You can average things out by simply selecting the closest multiple of 1024 to that amount just to keep it simple, so we'll say 10 x 1024= 10240mb and enter that amount in the field for "Memory to use (MB)". We are still well within the 13GB of unused memory BUT we have left enough memory unused so that if Windows decides to load some other process or background program, or an already loaded one suddenly needs more, we won't run into a situation where the system errors out due to lack of memory because we've dedicated it all to testing.

I've experienced false errors and system freezes during this test from over allocating memory, so stick to the method above and you should be ok.


Moving right along, do not change the time to run each FFT size.Leave that set to 15 minutes.

Click run and run the Custom test for 8 hours. If it passed Memtest86 and it passes 8 hours of the Custom test, the memory is 100% stable, or as close to it as you are ever likely to get but a lot of experts in the area of memory configuration suggest that running the extended Windows memory diagnostic test is also a pretty good idea too.

If you get errors, (and you will want to run HWinfo alongside Prime95 so you can periodically monitor each thread as Prime will not stop running just because one worker drops out, so you need to watch HWinfo to see if there are any threads not showing 100% usage which means one of the workers errored and was dropped) then you need to either change the timings, change the DRAM voltage or change the DRAM termination voltage, which should be approximately half of the full DRAM voltage.

There are also other bios settings that can affect the memory configuration AND stability, such as the VCCIO and system agent voltages, so if you have problems with stability at higher clock speeds you might want to look at increasing those slightly. Usually, for Intel at least, something in the neighborhood of 1.1v on both those is pretty safe. There are a substantial number of guides out there covering those two settings, but most of them are found within CPU overclocking guides so look there in guides relevant to your platform.

As a further measure of assurance that your WHOLE configuration is stable, you can download and run Realbench for 8 hours. If the system freezes or fails when running Realbench with your full memory amount set, try running it again but select only half your amount of installed memory.
 
Reactions: superfrillz12
Are you playing at 1080P or 1440P? Perhaps the CPU overclock might actually get you something if you have a 144 Hz monitor....; naturally, if playing at 4k, the CPU would do about the same at 4.5 GHz as it would at 5 GHz....)

(Oh, as the turbo of the 8700K is 4.7 GHz anyway, do you mean you are simply running all cores at that clock, which is as easy as enabling MCE on an Asus mainboard?)
 

superfrillz12

Prominent
Jun 15, 2018
13
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Are you playing at 1080P or 1440P? Perhaps the CPU overclock might actually get you something if you have a 144 Hz monitor....; naturally, if playing at 4k, the CPU would do about the same at 4.5 GHz as it would at 5 GHz....)

(Oh, as the turbo of the 8700K is 4.7 GHz anyway, do you mean you are simply running all cores at that clock, which is as easy as enabling MCE on an Asus mainboard?)
Hi yes I am playing at 1080, I looked at 1440p monitors but they are expensive so I just limit my FPS to 75 which is my refresh rate. My clock is 4.7ghz on all cores but MCE is off because it overvolts
 

Darkbreeze

Titan
Moderator
Oh, as the turbo of the 8700K is 4.7 GHz anyway, do you mean you are simply running all cores at that clock, which is as easy as enabling MCE on an Asus mainboard?
I don't know why some people continuously recommend running automatic features, both overclocking and tuning, that we know tend to use overkill voltage to err on the side of stability, when a person can easily do the same thing themselves manually with much less voltage and heat. Seems lazy, but I get it, some users can't be trusted to safely do things manually. Clearly, this user is not among those though since he obviously has a handle on what he's doing.
 

superfrillz12

Prominent
Jun 15, 2018
13
0
510
0
I don't know why some people continuously recommend running automatic features, both overclocking and tuning, that we know tend to use overkill voltage to err on the side of stability, when a person can easily do the same thing themselves manually with much less voltage and heat. Seems lazy, but I get it, some users can't be trusted to safely do things manually. Clearly, this user is not among those though since he obviously has a handle on what he's doing.
Is it possible to run c states with a manual overclock like mine?
 

Darkbreeze

Titan
Moderator
I always do. On all my overclocked systems, unless I am setting up a folding or scientific calculation machine for somebody that will be running almost entirely full bore at all times, I leave or enable the C states and then also set the power plan in control panel to performance BUT then go into the advanced settings of the performance power plan and set the minimum processor power state setting to 8-10%. Usually, 8%. The amount of time it takes to jump from idle to full speed is milliseconds. Technically, you could see milliseconds of lag if a game engine is frequently switching between the number of active cores, but honestly, a human would be incredibly unlikely to ever notice or detect that. It happens so fast that it might as well be instantaneous.

The difference isn't overwhelming, you might save 10-20 dollars per year on your energy bill, HOWEVER where you WILL see the difference is on package temps. A CPU that gets the ability to cool cores when they are not explicitly needed will see lower long term average package temps and CAN see lower overall short term temps if there is not simply a call for 100% all core operation and that is rarely the case. Power savings aside, that can mean a lot longer life for an overclocked, or even stock, CPU and for the motherboard VRM components as well.
 

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