i7 9700k undervolt guide?

[Guest]

Hi,

 

After successfully undervolting my (fairly) new GPU, and seeing the massive difference in temps I was getting for at least similar/advertised performance levels, I wondered if the same could be done for my CPU, which is an intel i7 9700k.

 

I'm not overclocking anything, so it runs at 3.6Ghz, and boosts usually to 4.6Ghz, occasionally 4.7 or 4.9 very briefly.

 

I tried using intel XTU software, but wasn't really sure where to start, since the basic tuning section applies to overclocking, which I don't want to do.

 

I took a look at the advanced section and played around with various "offset" figures, eventually settling on -0.065V.

 

XTU doesn't seem to save settings or give an option to run at boot that I could see though, so I'd have to manually do this every boot.

 

So I looked into doing it in bios, and I THINK i've managed to set the voltage to "offset" mode and set it to -0.065 there.

 

There were also 4 different limits which I've set to max (I think the values where 4095, 4095, 255.xx and 127.xx, can't rememebr the exact values for the last 2) in the bios. I did this because otherwise the XTU stress test shows power limit throttling.

 

I have seen a reduction in temperatures (for example, the xtu stress test & bench previously reached 80+,rapidly fluctuating from 75 to 84, this now hovers around 69 to 74....and annecdotally, in games temps seem to hover around 50-65 depending on load, which is fine).

 

My main question is, have I done it right? is the offset mode the best way to do it? or should I be somehow trying to actually pick a set voltage? e.g. 1.2V or whatever?

 

Does -0.065 sound about right? it jsut doesn't seem like a massive difference in voltage? 65mv?

 

I found that I could push it a bit further, like -0.075 or possibly -0.080, but below that I was getting blue screens pretty quick, so I figured I'd just pick a figure that was a little higher? is that the right thing to do? -0.065 gave me exactly the same XTU benchmark score as I got at 0.0, whereas lower voltage did start dropping the score, even though clock speeds where the same :s

 

I'm jsut very new to all of this, and trying to get same performance as stock/default, but lowest possible temperatures.

 

I know the temps now are fine, but I'm just left wondering if there's still room for improvement, or if I've even done it the correct way? a lot of the guides I've seen aren't very begginner friendly, or they contradict eachother, so just hoping that soemone can either ease my mind by confirming that what i've done sounds about right, or point me in the right direction to get the best results.

 

 

[Noah0302]

I think you will be able to go even lower.

A friends 9700k manages to hit 5GHZ Overclock with 1.325 Volts, so if you dont even have it OCed then just try to go lower until its unstable. Cinebench R23 Render Test is a good way to start, but if you want to be 100% sure its stable then try running Prime 95

[Guest]

3 minutes ago, Noah0302 said:

I think you will be able to go even lower.

A friends 9700k manages to hit 5GHZ Overclock with 1.325 Volts, so if you dont even have it OCed then just try to go lower until its unstable. Cinebench R23 Render Test is a good way to start, but if you want to be 100% sure its stable then try running Prime 95

Thanks for your reply. Am I doing it the correct way though? just setting an offset? or should I be trying to find a specific value to "set" the volatage at?

[Guest]

12 hours ago, Noah0302 said:

I think you will be able to go even lower.

A friends 9700k manages to hit 5GHZ Overclock with 1.325 Volts, so if you dont even have it OCed then just try to go lower until its unstable. Cinebench R23 Render Test is a good way to start, but if you want to be 100% sure its stable then try running Prime 95

Just managed to do a bit more testing. After I disabled mce in the bios, -0.095 still caused blue screen, but -0.090 seems ok. I haven't run prime95 for an extended time, but all the xtu stress tests pass (I ran all 4, at 5 minutes each, one after the other).

 

Timespy cpu test also runs fine, no crashes.

 

Didn't see a massive reduction in temps at -0.090 compared to -0.065 mind you, but even in the stress tests, it's still not going above 70, so that's perfectly safe.

 

Perhaps I'll notice a bigger impact when I'm just generally gaming, rather than constantly throwing cpu stress tests at it haha.

[Guest]

13 hours ago, Noah0302 said:

I think you will be able to go even lower.

A friends 9700k manages to hit 5GHZ Overclock with 1.325 Volts, so if you dont even have it OCed then just try to go lower until its unstable. Cinebench R23 Render Test is a good way to start, but if you want to be 100% sure its stable then try running P

Nope.....-0.090 still caused bsod using timespy extreme. Urgh.... back to the drawing board.

[Guest]

Definitely -0.065 is as far as I can push. Didn't get time to fully test yesterday, but will do more after work today. Just posting in case anyone else with i7 9700k had been reading online and wondering how much/little of an undervolt they might get. It doesn't seem like a lot to me, but it does still reduce temps, so as long as it's stable I'll keep it. 

[xg32]

 

i recommend using fixed voltage for undervolting, since big negative offsets can sometimes cause idle bsods. Look at what the actual vcore under load is, use that as a fixed voltage with a low LLC to transition over. -.08v is around where i'd expect things to be unstable on idle

 

Here's the voltage table for my below-average 9900k, stock is 1.3v 4.7ghz and if i used a negative offset of -.1v system wouldn't even turn on.

 

4.4ghz 1.05v

4.7 1.18v

5.1 1.36v

5.2 1.395v

 

I use 4.4 when i play 2d games so the cpu doesn't spike to 100w, 5.1 is useful for stuff like hitman/2077, and work

 

 

[Guest]

21 hours ago, xg32 said:

 

i recommend using fixed voltage for undervolting, since big negative offsets can sometimes cause idle bsods. Look at what the actual vcore under load is, use that as a fixed voltage with a low LLC to transition over. -.08v is around where i'd expect things to be unstable on idle

 

Here's the voltage table for my below-average 9900k, stock is 1.3v 4.7ghz and if i used a negative offset of -.1v system wouldn't even turn on.

 

4.4ghz 1.05v

4.7 1.18v

5.1 1.36v

5.2 1.395v

 

I use 4.4 when i play 2d games so the cpu doesn't spike to 100w, 5.1 is useful for stuff like hitman/2077, and work

 

 

Thanks.

 

I'm now testing disabling mce and speedstep, and syncing all cores to 46. Tested vcore at 1.15 but crashed. Moved it up to 1.18 and seems ok so far. 

 

One thing im still not very clear on.... is it just vcore voltage that I should be setting in bios? There's so many different settings there and I've never set a manual voltage like this before. 

 

The options in bios are for

 

Cpu core voltage override

Cpu vccio voltage

CPU system agent voltage

Pch core voltage

Cpu standby voltage

 

Which of these should I change, and do I set ALL of them the same 1.18?

[xg32]

9 hours ago, Glenn-Tidbury said:

Thanks.

 

I'm now testing disabling mce and speedstep, and syncing all cores to 46. Tested vcore at 1.15 but crashed. Moved it up to 1.18 and seems ok so far. 

 

One thing im still not very clear on.... is it just vcore voltage that I should be setting in bios? There's so many different settings there and I've never set a manual voltage like this before. 

 

The options in bios are for

 

Cpu core voltage override

Cpu vccio voltage

CPU system agent voltage

Pch core voltage

Cpu standby voltage

 

Which of these should I change, and do I set ALL of them the same 1.18?

only change the first 1, the rest should be auto in ur case

[Guest]

 

thanks for your help

 

 

[Guest]

1.16 seemed fine, prime95 ran without errors for 45 minutes.... but then it just closed. PC didn't crash, but the program did.

 

Testing 1.17 now.

 

I just read the part about llc....I haven't touched that setting. Im not overclocking, in fact, I technically underclocking? since cores are all synced to max 46.... so do I still keep llc at default? 

[Guest]

So confused. Trying to read online to work out what temps I should be expecting, and even with an overclockers CPU, I've seen people saying that anything above 80 is in the danger zone? Well, I'm underclocking, undervolting, fans going crazy, and yet prime95 is still reaching max of 82 according to afterburner charts.... and that's just the general cpu temp that it displays, and as I understand it, core temps will be even higher? 

 

It basically runs for about 5 minutes at 60ish, 5 at 70ish, 5 at 80ish, 5 at 70ish then repeats..... this is at 4.6ghz and vcore voltage at 1.170.

 

It's water cooled, and has 2 intake and an extra top exhaust fans as well as the 2 fans attached to the radiator at the back. 

 

Shouldn't temps be lower? It's still running after an hour, and no workers have stopped or shown any errors so far as I can see. 

[ZeroLine]

1 hour ago, Glenn-Tidbury said:

So confused. Trying to read online to work out what temps I should be expecting, and even with an overclockers CPU, I've seen people saying that anything above 80 is in the danger zone? Well, I'm underclocking, undervolting, fans going crazy, and yet prime95 is still reaching max of 82 according to afterburner charts.... and that's just the general cpu temp that it displays, and as I understand it, core temps will be even higher? 

 

It basically runs for about 5 minutes at 60ish, 5 at 70ish, 5 at 80ish, 5 at 70ish then repeats..... this is at 4.6ghz and vcore voltage at 1.170.

 

It's water cooled, and has 2 intake and an extra top exhaust fans as well as the 2 fans attached to the radiator at the back. 

 

Shouldn't temps be lower? It's still running after an hour, and no workers have stopped or shown any errors so far as I can see. 

9th gen runs hot so that's expected. My undervolted 9900KS at 5ghz 1.170V starts at high 80s and peaks at high 90s on the hottest core.

[Guest]

41 minutes ago, ZeroLine said:

9th gen runs hot so that's expected. My undervolted 9900KS at 5ghz 1.170V starts at high 80s and peaks at high 90s on the hottest core.

I can't get anything to be stable with prime95....

 

Even up to 1.2v with capped speed of 4.6ghz..... still get workers stopping after an hour and a half. 

[Guest]

Thing is, I don't even dare to test letting prime95 run at stock for any length of time because instead of 60,70,80ish..... it's more like 75, 85, 95.... I can't let the cpu sit there for 10 hours at those high temps :s

 

so I just have to assume that, at stock, it's stable, but hot.

 

urgh.... literally spent all weekend trying to get this right. fail. 

[ZeroLine]

6 hours ago, Glenn-Tidbury said:

I can't get anything to be stable with prime95....

 

Even up to 1.2v with capped speed of 4.6ghz..... still get workers stopping after an hour and a half. 

Under load voltage droops relative to current pulled. My 1.170v figure is from the vrvout sensor after droop - before droop it's 1.3-1.4v. If you left LLC on auto, you'd likely have to use a voltage higher than 1.2v for stability due to vdroop.

[Guest]

 

This is all so complex. So many different figures and settings. I can see why people buy consoles now.

 

Just going to leave it on default. Thanks for trying.

 

::EDIT:: using voltage above 1.2V doesn't reduce temperatures, so at that point, may as well stick with default settings and not have boost speed limited to 4.6Ghz instead of 4.9Ghz.

[Guest]

9 hours ago, ZeroLine said:

Under load voltage droops relative to current pulled. My 1.170v figure is from the vrvout sensor after droop - before droop it's 1.3-1.4v. If you left LLC on auto, you'd likely have to use a voltage higher than 1.2v for stability due to vdroop.

If i was to give this one more try.....what should i set llc to? mobo is tuf z370 gaming plus ii.

 

I jsut can't understand why people with the same cpu as m, are getting OVERLCOCKS at low volatges and low temps, compared to my undervolt without really overclocking (4.6Ghz is the boost clock anyway).

 

Do I just have a bad CPU?

 

I also have now seen a lot of people talking about using avx offset......but all that does is bring the clock down....i don't understand why I'd want to set clock at 4.6Ghz and then have it downclock to 4.4 or whatever if i set an avx offset of -2......why not just set clock at 4.4 to begin with?

 

I wish i could find a really easy, step by step guide for all of this......i just want to keep my temps low and maintain normal stock speeds....but it seems like every time i get close, there's another piece of the puzzle to try and work out, or soemthing that seems stable in benchmarks and gaming stress tests, actually fails a lot under cpu specific tests.

[ZeroLine]

55 minutes ago, Glenn-Tidbury said:

If i was to give this one more try.....what should i set llc to? mobo is tuf z370 gaming plus ii.

 

I jsut can't understand why people with the same cpu as m, are getting OVERLCOCKS at low volatges and low temps, compared to my undervolt without really overclocking (4.6Ghz is the boost clock anyway).

 

Do I just have a bad CPU?

 

I also have now seen a lot of people talking about using avx offset......but all that does is bring the clock down....i don't understand why I'd want to set clock at 4.6Ghz and then have it downclock to 4.4 or whatever if i set an avx offset of -2......why not just set clock at 4.4 to begin with?

 

I wish i could find a really easy, step by step guide for all of this......i just want to keep my temps low and maintain normal stock speeds....but it seems like every time i get close, there's another piece of the puzzle to try and work out, or soemthing that seems stable in benchmarks and gaming stress tests, actually fails a lot under cpu specific tests.

Unfortunately, I've only had experience with z390 boards and the 9900k/s so I can't help you there. I've seen people in forums reporting difficulty in undervolting and overclocking their 9700k/9900k on a budget z370 board, which no longer happened when they upgraded to z390 boards. If it works at stock then just leave it as it or go with a conservative undervolt like -0.030v.

[Guest]

4 minutes ago, ZeroLine said:

Unfortunately, I've only had experience with z390 boards and the 9900k/s so I can't help you there. I've seen people in forums reporting difficulty in undervolting and overclocking their 9700k/9900k on a budget z370 board, which no longer happened when they upgraded to z390 boards. If it works at stock then just leave it as it or go with a conservative undervolt like -0.030v.

ok, thanks for your reply, appreciate all the info you've given.

from what I can gather, LLC is there to prevent voltage spikes....so, sin'ce I'm trying to LIMIT the voltage and kep cores at 4.6 anyways, I'm not sure how it could be spiking MORE than it would at default settings, when it has more voltage to begin with :s

 

Difficulty is, with manual voltage, 1.2 or above, temps are pretty much the same as stock...so....no point undervolting.....but anything below that seems to either crash prime95, or cause workers to stop after 1-2 hours.

 

If i use offset mode, then anything above -0.065 and the temperatures, again, don't really drop enough to make it worth doing. but at -0.065 and below, prime95 issues crop up.

 

I can leave it at stock, but i'm not brave enough to let prime95 run for any great length of time because of the temps, so I just have to work off the assumption that it's stable :s

 

Whenever i try any of the "auto tuning", "eztuning", or any of the preset overclocked profiles, it always gives me bsod, so i have to just leave it on standard mobo defaults and accept that it gets way hotter than I think it should for a water cooled system.

[Guest]

Currently testing 1.35V, LLC 2, but keeping other settings at default, I.e. not syncing all cores to 46. Prime 95 running, clock is still rock solid 4600, and 15 minutes into the test, max temp has been 78C... which is fine, as im really just hoping to keep things below 80. Fingers crossed 1.35V should be enough to keep things stable I'd have thought! 

 

I don't know why the temps are now staying below 80 though....I'm sure when I checked the voltages before I started all this, it was only ever drawing around 1.33V before.... so why should it now have lower temps when I've technically raised the max voltage by .02V?

 

Im baffled.... but if things stay low and stable I'll be happy. 

[Guest]

Oh man....3 hours without any errors and temps below 80.... leave it running for another 7 hours? Or experiment with reducing voltage by 0.001?

 

::EDIT::

 

decided to test some other values.....but turns out 0.001 isn't an optin lol, only 5mv increments.

 

1.330V lasted 1 hour.

1.34V lasted 2.5 hours.

I know that 1.35V lasted well over 4 hours....

 

so rather than let that continue to run it's course, I'm testing 1.345V and hoping that extra 0.005V is enough to keep it stable.

 

Fingers crossed.

[Guest]

just in case anyone comes accross this in the future, i've actually jsut found an "overlocking" guide on reddit for the 9700k.

 

I know it's not technically what I'm trying to achieve, but I might give it a go anyway later (maybe setting multiplier lower than 50 though, since I'm really not aiming for a huge overclock, just want it stable, performing well and not too hot.

 

interestingly though, they reccommend starting with 1.30V (lower thanI'm currently able to achieve with the settigns I've got in bios), but at 5Ghz....and they've also got a higher LLC, and they also changd another setting called SVID, which I didnt touch....

 

anyway, this is what the reddit gudie said:-

 

"The only time the stock 9700k will boost to 4.9Ghz is if 1 or 2 cores are under load ONLY. If 3 or 2-4 cores are, it will drop to 4.8Ghz, and if all 8 are loaded it will go to 4.6Ghz (which is what you saw).

I strongly recommend never using profiles for overclocking as they generally overvolt like crazy since they are generic profiles.

If you would like to try a basic, but likely stable, 5Ghz overclock, reset everything in the BIOS to default and then follow these steps:

1. Enable XMP for RAM

2. Set CPU Core Ratio to "Sync All Cores" and set the multiplier to 50

3. Disable ASUS Multi Core Enhancement

4. Disable CPU SVID

5. in "External Digi+ Power Control" set Loadline Calibration (LLC) to level 6, and CPU Current Capability to 170%

6. Set CPU Core/Cache Current limit to 9999 (should change to 255.70 or something similar)

7. Change CPU Core/Cache voltage to Manual, 1.30v

8. Go to "Internal CPU Power Management", set both Short Duration and Long Duration Power Limits to max (4095)

Save and exit. Check stability and temps while stress testing, if stable after 10 minutes, go back into BIOS and reduce voltage by .01v (IE 1.29v) and repeat the test. Keep doing this until it is no longer stable, then set to the last stable voltage. You can go to a third decimal point if you want, but it's not really necessary."

[Guest]

Vcore at 1.345 LLC2 seems to be fine.....just checked, it's still running prime95 after nearly 8 hours and going strong. temps on the extreme parts of the test range between 75 and 78, occasionally popping up to 80 just for a second or less. Clock is at a rock solid 4.6Ghz. I'll leave it for a couple hours more, but seems pretty stable and is achieving the temps I wanted I think.

 

Still interested to try the suggested method found on reddit earlier.....but at least now I know I have a working option to use. 1.345V still seems high to me for 4.6Ghz, as I've seen people mention before that they ahve gotten 5Ghz at 1.300.....but maybe it';s jsut down to cooling and the silicon lottery? In any case, I seem to be getting the results I was hoping for Rock solid core clock, no throttling down, and temps within a safe limit.

 

Will post again after I try the other method.

[Guest]

Ok, so I tried the other method from reddit..... crashed....a lot.... maybe because my mobo doesn't have an option to disable svid? Dunno. 

 

Anyway, the previous setting I had was stable in prime 95 for 10 hours and temps never went above 80.... in fact, for some reason, in the last 2 hours of the tests, it never went above 65.

 

Xtu stress tests also pass, temps never go above 72 and mostly hover between 60 and 70, even in the avx2 test. No throttling of any kind, no high temps and clocks stay at 4.6hz all the time.

 

Hwmonitor also doesn't report vcore being above 1.312.... maybe it's not that accurate? Who knows.... anyway, I'm happy with the setup now I think.... time to finally get some games played.