Question I9-9900KS - dwnclock / lower voltage?

Feb 24, 2020
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Hello,

I am running an I9-9900KS and feel that my temps are hitting very high while gaming and it fluctuates a lot which I am not a big fan of.

While idling / light load I am at 32-46c and it jumps a lot back and forward. While gaming I can reach as high as 90c which doesn't seem right to me.

I have checked and ensured there isn't a plastic cover on the cooler, I replaced the thermal paste with Thermal Grizzly Kryonaut (even re-done it to ensure it was applied evenly). All fan and CPU settings are set too 100%.

My MOBO has been updated to the latest BIOS which is F9c.

Unless someone has had a similar issue and managed to fix it and could shed some light upon this how do I go about underclocking my CPU?

Everything is set to auto apart from XMP. CPU volt sits at between 1.34x to 1.37x depending on load.

Do I just follow a standard overclocking guide, but instead of increasing cores just lower voltage to see where my stability is?

I tried prime95 without AVX and CPU hits 100c in less than 5 mins.

Full PC specs:

MOBO: Z390 Aorus Xtreme
CPU: i9-9900KS
COOLER: NZXT X72 Kraken
RAM: 32 GB (3600 mHZ) Corsair Vengeance RGB PRO
PSU: HX1000i
GPU: Aorus 2080 Ti xtreme
Case: NZXT H710i

Radiator is mounted top as an exhaust
3 in take fans front, 1 exhaust fan rear
 

MadsModsat

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If you haven't already, you could look at VCCIO voltage og VCCSA (System Agent) voltage as the BIOS XMP setting often set these values a bit on the high side on auto.

I have the standard i9 9900K and an AIO 280mm cooler (fans set to never exceed 750 RPM), and I lowered IO and SA from auto 1.328v and 1.264v to manual 1.100v and 1.150v, it lowered Prime95 AVX Small FFTs temps by approximately 4-5'c.
After 20 minutes of P95 Small FFTs with AVX my CPU Package sits at 79'c with one of the cores hitting 81'c at one point. The extra 300MHz all core is expensive when it comes to temperatures, I must say.

I haven't tested with the fans spinning faster, as the noise annoys me, and I wanted temperatures that would simulate my daily use.

It's not much, but it is better than nothing, and you also avoid runing excessive voltages unneccesarily.
But I have no idea if or how much the thermals of the 9900KS will be improved considering the 300MHz higher all core.

My RAM are only 3333MHz with fairly average timings though, so you might need a bit more IO and SA voltage for 3600MHz, it might be neccessary with a little trial and error testing.

It should also be possible to shave a little bit off the Auto Vcore as well, but I don't have hands on experience with the KS model so I can't say precisely what you would be looking at, but somone else will know for sure.

You could also try an AVX negative offset value, so your CPU downclocks when running AVX workloads.

EDIT: But generally you will never really see Prime95 AVX type workloads in everyday use, so don't focus too much on that. Usually it is recommended to disbale AVX when running P95.
But 90'c when gaming seems quite hot (depending on the game. Battlefield V, for instance, uses AVX, and will run the CPU hotter than a lot of other games).
 
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Feb 24, 2020
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If you haven't already, you could look at VCCIO voltage og VCCSA (System Agent) voltage as the BIOS XMP setting often set these values a bit on the high side on auto.

I have the standard i9 9900K and an AIO 280mm cooler (fans set to never exceed 750 RPM), and I lowered IO and SA from auto 1.328v and 1.264v to manual 1.100v and 1.150v, it lowered Prime95 AVX Small FFTs temps by approximately 4-5'c.
After 20 minutes of P95 Small FFTs with AVX my CPU Package sits at 79'c with one of the cores hitting 81'c at one point. The extra 300MHz all core is expensive when it comes to temperatures, I must say.

I haven't tested with the fans spinning faster, as the noise annoys me, and I wanted temperatures that would simulate my daily use.

It's not much, but it is better than nothing, and you also avoid runing excessive voltages unneccesarily.
But I have no idea if or how much the thermals of the 9900KS will be improved considering the 300MHz higher all core.

My RAM are only 3333MHz with fairly average timings though, so you might need a bit more IO and SA voltage for 3600MHz, it might be neccessary with a little trial and error testing.

It should also be possible to shave a little bit off the Auto Vcore as well, but I don't have hands on experience with the KS model so I can't say precisely what you would be looking at, but somone else will know for sure.

You could also try an AVX negative offset value, so your CPU downclocks when running AVX workloads.

EDIT: But generally you will never really see Prime95 AVX type workloads in everyday use, so don't focus too much on that. Usually it is recommended to disbale AVX when running P95.
But 90'c when gaming seems quite hot (depending on the game. Battlefield V, for instance, uses AVX, and will run the CPU hotter than a lot of other games).
Thanks for your reply dude.

I will look into that when I get home. Would it be better for me to start lowering my vcore at a higher interval and then go lower. Say 1.3v and then 1.295 if stable and so on??

It gets to 87c on call of duty modern warfare lol which seems insane to me! I know I'll probably never reach Prime95 in terms of work loads, but my OCD kicks in and it just doesn't feel right.

Another guy (on this forum, with a custom loop) got 25c idle and 70c on max load.. mine would be hotter as I am not using a custom loop, but you'd assume that 90-95c would be max during 100% load lol.
 

MadsModsat

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I used to work my way up, until the CPU got too hot or ran stable.

But since you are looking at doing the opposite - you already know your CPU is stable at a certain voltage - I think it makes sense working your way down, as you suggested.

I know I saw someone post a decent stable Vcore for the i9 9900KS @ stock frequencies, I just don't remember where - it would have been a good base line for comparison. I know all chips aren't created equal and you never can compare 1:1, but the KS are supposed to be the best you can get, so it would have been interesting to see a comparison. I believe the Vcore posted was in the 1.28-something-something range, but I can't be sure.

I know what you mean regarding the temperatures, I'm still uncomfortable when my CPU rises above the 70'c-ish mark (which is not actually unsafe in any way), so I have set everything up, so I max out at 69'c unless I'm stresstesting. But even the ordinary 9900K is a hot chip, and the 9900KS even more so. So you will probably have to adjust to seeing higher temps than you are comfortable with, BUT you should definately be able to run it at stock settings with a 360mm AIO.

I clocked my 9900K to an all core 5.0GHz just to see if it could do it, and I was able to manage the temperatures even with my 280mm AIO.

I'm running stock settings again, as it was good fun for some benchmarking, but I don't really need 5 GHZ all core clock everyday and I didn't like the temp it resulted in.
 

chrysalis

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Here is my values, if you on stock clocks or a slight overclock try these as a starting point. I have 4 dimms so if you only have 2 you can probably reduce VCCSA to 1.15v.

VCCIO 1.1v
VCCSA 1.2v
Vcore (fixed) 1.25v
I also reduced VCCPLL but cannot see the reading in hwinfo to grab for you, when I next check in bios if I remember I will update here.

Note I have the 9900k not 9900ks.
 
Feb 24, 2020
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Here is my values, if you on stock clocks or a slight overclock try these as a starting point. I have 4 dimms so if you only have 2 you can probably reduce VCCSA to 1.15v.

VCCIO 1.1v
VCCSA 1.2v
Vcore (fixed) 1.25v
I also reduced VCCPLL but cannot see the reading in hwinfo to grab for you, when I next check in bios if I remember I will update here.

Note I have the 9900k not 9900ks.
That is dude and to the other fella for the response.

What I'll do is I'll lower volt to 1.3 and see how stable it is. Do I have to activate anything else before I continue ??
 

MadsModsat

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I would suggest you use adaptive voltage instead of fixed (override), it will help lower the idle temp - there's no reason to have it sit at max vcore setting when idle or under light loads - the idea was to reduce operating temperatures.

You are not pushing a massive overclock to the limit, your CPU is confirmed stable and designed to operate with a vcore that increase or decrease with the workload. As far as I understand you just want it running at lower temps as an everyday desktop PC as close as possible to the default Intel voltages, not for pushing the CPU beyond its limit.

You generally can't compare the needed Vcore for a K-model at 5 GHz all-core 1:1, as a KS-model will reach that frequency at lower voltages due to the higher silicon quality / top binning.

But it is probably a good starting point.
 
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Feb 24, 2020
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I would suggest you use adaptive voltage instead of fixed (override), it will help lower the idle temp - there's no reason to have it sit at max vcore setting when idle or under light loads - the idea was to reduce operating temperatures.

You are not pushing a massive overclock to the limit, your CPU is confirmed stable and designed to operate with a vcore that increase or decrease with the workload. As far as I understand you just want it running at lower temps as an everyday desktop PC as close as possible to the default Intel voltages, not for pushing the CPU beyond its limit.

You generally can't compare the needed Vcore for a K-model at 5 GHz all-core 1:1, as a KS-model will reach that frequency at lower voltages due to the higher silicon quality / top binning.

But it is probably a good starting point.
Sorry, bit of a noob but how do I set to be adaptive? 🤣
 

MadsModsat

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I apologize, I'm not familiar with Gigabyte's BIOS/UEFI so I'm wrong here concerning the names. Apparently Adaptive Voltage is an ASUS specific thing, Gigabyte calls it "dynamic voltage" or DVID, and as far as I can understand, you must set CPU Vcore to NORMAL to be able to set the Dynamic Voltage (DVID) which is directly under CPU Vcore in BIOS.

But you should look it up before changing it, to be sure exactly what the correct setting should be.
 
Feb 24, 2020
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I apologize, I'm not familiar with Gigabyte's BIOS/UEFI so I'm wrong here concerning the names. Apparently Adaptive Voltage is an ASUS specific thing, Gigabyte calls it "dynamic voltage" or DVID, and as far as I can understand, you must set CPU Vcore to NORMAL to be able to set the Dynamic Voltage (DVID) which is directly under CPU Vcore in BIOS.

But you should look it up before changing it, to be sure exactly what the correct setting should be.
After hours on end of reading as many posts I could find in regards to my temps, I seen a post on reddit from someone who had their X72 kraken as a top mount and they had very high temps. When removing the top panel, temps dropped.

I'll check mine now and have a look.

I tried setting vcore to 1.3 but unstable, if not I'll figure out the whole adaptive volt mess and see if it works.

Not familiar with downvolting, overclocking is easier as there are 100s of guides and even from gigabyte themselves how to reach 5 ghz with an i9-9900k l...
 

MadsModsat

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It is surprisingly difficult to find good information regarding actual manual voltage settings for a complete default setup and stock values. I was struggling with that myselft, when I wanted to lower the auto voltage vcore and IO + SA auto voltages for my 9900K. I can find tonnes of posts about acheiving a 5GHz all core overclock, but it took some time to find information about going in the opposite direction. It's the same with the 9900KS, only all threads are about achieving 5.2GHz or more.

What I did was use the same settings I'm using when overclocking, but applying different offset values and as close to Intel spec voltages as I could find. Offset values can be used to find the perfect balance between Vcore, stability and heat. But you can kinda use it in reverse too.

edit : remember to only adjust one value at a time. If you lower both vcore, vccio and vccsa at once, you won’t know what setting is causing instability.

edit II : What you could do, if you decide to underclock by lowering the multipliers, is to set a “per core” multiplier, which means you can set individual multipliers for each core. Then set 4 cores multiplier at 50 (for 5GHz) and 4 cores at 49 (for 4.9GHz). Then your CPU will run at 4.9GHz when all cores are utilized, but will still boost to 5GHz when 4 cores or less are utilized. I did that when experimenting with overclocking my 9900K, and it had a very positive impact on max load temps, compared to all-core 5GHz.
But still, mine was an overclock, so not identical circumstances as with your KS.
I always benchmark when I overclock, and setting the cores as suggested above would be more measurable than actually percievable.
And as I initially mentioned, you could consider running a negative AVX offset.
But I still beleive your CPU should be able to run default setting with your cooler.
 
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Phaaze88

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The 9900KS shouldn't be getting that bloody hot...
Are you sure the Kraken's pump is running? With your hands, check everything while the unit is running:
-cpu block
-tubing
-radiator
None of them should be particularly cool, save for maybe the 'return to cpu block' tube.
 
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Feb 24, 2020
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@MadsModsat thanks dude, I took the top of my tower and it is a bit cooler, I am going to try to do a front mount and see if it helps with temps and if not test it with my H100i V2 aio. I got in touch with a fella on reddit who is running 5 ghz on his at 1.24 volts stable.

@Phaaze88 I am positive it is running, the radiator was warm, the block bit was very warm, didn't check the tubing though.

Though if the pump was faulty surely I would be getting even higher temps??
 

Phaaze88

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Though if the pump was faulty surely I would be getting even higher temps??
No, because 100C is the critical temp on that cpu. It would've forced a shut down had you continued with your testing.

It appears the radiator is running fine.

I'm lead to believe the issue lies with the motherboard - the auto settings, to be more precise.
That particular motherboard does not adhere to Intel's TDP specifications and it's being FAR too generous on the additional voltage.
Your cpu is essentially a cherry picked sample of the 9900K; it should be capable of running 5.0ghz at less voltage than the former.

Now that I think about it, don't some people with a 9900K achieve 5.0ghz at something like 1.24-1.27v?
IF that's true, then your motherboard's auto settings are set WAY too high...
 
Feb 24, 2020
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No, because 100C is the critical temp on that cpu. It would've forced a shut down had you continued with your testing.

It appears the radiator is running fine.

I'm lead to believe the issue lies with the motherboard - the auto settings, to be more precise.
That particular motherboard does not adhere to Intel's TDP specifications and it's being FAR too generous on the additional voltage.
Your cpu is essentially a cherry picked sample of the 9900K; it should be capable of running 5.0ghz at less voltage than the former.

Now that I think about it, don't some people with a 9900K achieve 5.0ghz at something like 1.24-1.27v?
IF that's true, then your motherboard's auto settings are set WAY too high...
I've just got a response from Intel as I contacted them after being asked to do a number of performance tests and send relevant data. They are stating everything is fine but noticed that I only have 3 ram modules installed, even though i have 4.

So what I'll do is to re-position the ram, make sure all are detected, if it's a no, I'll test them individually to see which is faulty. If it turns out all are working ill have to RMA the board.

I will also in the meantime contact Gigabyte support and ask them about the voltage and what I am experiencing... typical my luck.. can never have anything nice without it all going wrong.
 

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