Question Clocks dropping on i9-9900K when Stress Testing

stevenj31696

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Dec 1, 2018
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So like the title says my clocks keep dropping on my 9900K when stress testing in Prime95 Smallest FFT's. I'm not even overclocking it yet, just trying to get it to run 5GHz all cores no AVX offset. I'm running a ASRock Extreme4 Z390 Mobo and 16GB G.SKILL Trident Z RGB 3000MHz. I'm not running the XMP, but am running the correct timings and voltages.

I'm not even getting any errors in Prime95 and I have the TJ Max temp set to 105c just for stress testing purposes since TJ max is actually 115.

However to even get it to run with no errors in Prime95 I am having to let it push past 1.4 vcore, all the way to 1.440 sometimes when running AVX enabled. It also does the same thing in Prime95 with AVX disabled (starts dropping core clocks and overall voltage). It's got me really confused atm, so any help is appreciated.

However, and this is the kicker, when I run Intel Burn test, Very High Stress level (cuz I don't have enough ram for Maximum) it stays pinned at 5GHz, 1.424 vCore. Passes no problem. Help please lol
 
'not overclocking it yet, just trying to get it to run 5 GHz on all cores'...

Running all cores at max turbo speed (MCE mode) is indeed overclocking,
Not every 9900K will maintain 5 GHz on all cores at even remotely reasonable temps, especially at 1.4+ V....on who's knows what cooling solution. (How can one discuss 9900K all-core temps and not even mention the cooling solution?)

Many mainboards have BIOS power limits that might be partiallly adhering to INtel specs, where a certain turbo might be maintained for 30 seconds or so, and then downclock to keep power consumption down to about 95-125W or so...

At all-core 5 GHz, the actual power draw is likely closer to 130-145 W....

You might need to remove all power limits, easy to do within Intel's XTU application...

Normal /defacto '100% load' with latest Prime95 is small (not smallest) FFTs, w/ assorted AVX disabled...; enabling even smaller FFTS with AVX loads is akin to a 110-120% torture load condition, or similar, and you can expect temps to be unmanageable quite often....(barring a supply of LN2)

So, redo your test as noted above, and see what temps are under a more normal stress test, vice the worst imaginable known to overload the CPU. (which is why AVX offsets exist, to step down clock speeds to keep things like heat and power draw in check!)
 
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MadsModsat

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Oct 10, 2019
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What are the clocks, that the CPU drops to when you are stresstesting?

As mdd1963 states above, an all-core 5GHz frequency on an i9 9900K, can only be acheived by overclocking.

Also, eventhough your goal is a 0 AVX offset, a lot of people have to use an AVX-offset in order to run their CPU at 5GHz all-core. It can be done of course, lots of people have already proven it, but not on every single setup.
If a very high voltage is needed to run a 0 offset AVX, you should consider if the performance gains are worth the very high voltage needed, or if it would be an idea to decrease the needed core voltage by adding an AVX offset.
A vcore of 1.44 is is in higher end of the scale for a 5GHz 9900K setup (although not above Intel spec), and for anything other than a bechmark PC, it is a high vcore for a "daily diver" - I'm impressed if you can keep the temperaturs under control at that voltage, it sounds like you have some very good cooling.

Many mainboards have BIOS power limits that might be partiallly adhering to INtel specs, where a certain turbo might be maintained for 30 seconds or so, and then downclock to keep power consumption down to about 95-125W or so...
Exactly, this is worth following up on

My ASUS motherboard throttles the CPU quite hard, even on stock settings, if I don't go into BIOS, and change the settings to allow for increased powerdraw, and also to remove limits on how long the CPU is allowed to exceed Intel spec 95W TDP.

If I change two or three settings in BIOS, my 9000K runs on boost clock for as long as is needed.

Some of the settings are adjusted automatically when enabling XMP, by the way, so since you aren't using the XMP profile, maybe it is worth noting, what changes the XMP profile makes in BIOS. IO and SA voltage comes to mind, they apply to RAM stability, among other things.
 
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