[SOLVED] PC is sluggish after i9 CPU upgrade

Renegade1911

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Jan 25, 2015
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Happy new year folks,

so recently I've updated from a i5 9600K to an i9 9900K. I know it's not the most sensible, but I could get it for a really good price and I had use for the i5 elsewhere. The i5 was overclocked to 5GHz. After swapping in the i9 (had to update Bios to get it to work at all), ran some test, didn't OC it yet, all seemed fine. But shortly after I started noticing sluggishness during normal usage. It's clearest when trying to switch Chrome tabs, file explorer windows etc. Also when quickly dragging around windows on the desktop I can clearly see it's stuttering and not running at high fps, as it would before (I have a 240Hz monitor). The strange thing is, if I start a CPU-Z stress test and all cores start running at 5GHz (temps max out at about 80C), everything speeds up again. The "window dragging" is now clearly crisp, same with tabs, even though all indicators say the CPU is under 100% load. But the second I stop it all slows down again. Videogame performance with this new CPU is improved where it can be, not much headroom with a 1080 Ti. So the issue seems isolated to, or at least only visible during light usage, which has me confused.

My full specs are:
CPU: i9-9900K
MB: Z390 Asrock Taichi (Bios version 4.20).
GPU: GTX 1080 Ti
RAM: 2x8GB at 3200MHz
SSD: Samsung 970 Evo
PSU: Something with 850W from Corsair, can't remember the specifics.

Any help would be much appreciated.
 

86zx

Upstanding
Nov 1, 2019
287
48
240
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Happy new year folks,

so recently I've updated from a i5 9600K to an i9 9900K. I know it's not the most sensible, but I could get it for a really good price and I had use for the i5 elsewhere. The i5 was overclocked to 5GHz. After swapping in the i9 (had to update Bios to get it to work at all), ran some test, didn't OC it yet, all seemed fine. But shortly after I started noticing sluggishness during normal usage. It's clearest when trying to switch Chrome tabs, file explorer windows etc. Also when quickly dragging around windows on the desktop I can clearly see it's stuttering and not running at high fps, as it would before (I have a 240Hz monitor). The strange thing is, if I start a CPU-Z stress test and all cores start running at 5GHz (temps max out at about 80C), everything speeds up again. The "window dragging" is now clearly crisp, same with tabs, even though all indicators say the CPU is under 100% load. But the second I stop it all slows down again. Videogame performance with this new CPU is improved where it can be, not much headroom with a 1080 Ti. So the issue seems isolated to, or at least only visible during light usage, which has me confused.

My full specs are:
CPU: i9-9900K
MB: Z390 Asrock Taichi (Bios version 4.20).
GPU: GTX 1080 Ti
RAM: 2x8GB at 3200MHz
SSD: Samsung 970 Evo
PSU: Something with 850W from Corsair, can't remember the specifics.

Any help would be much appreciated.
Possibly windows is in a lower power state so it’s dramatically down clocking the cpu so the response time is slow
 

86zx

Upstanding
Nov 1, 2019
287
48
240
6
Happy new year folks,

so recently I've updated from a i5 9600K to an i9 9900K. I know it's not the most sensible, but I could get it for a really good price and I had use for the i5 elsewhere. The i5 was overclocked to 5GHz. After swapping in the i9 (had to update Bios to get it to work at all), ran some test, didn't OC it yet, all seemed fine. But shortly after I started noticing sluggishness during normal usage. It's clearest when trying to switch Chrome tabs, file explorer windows etc. Also when quickly dragging around windows on the desktop I can clearly see it's stuttering and not running at high fps, as it would before (I have a 240Hz monitor). The strange thing is, if I start a CPU-Z stress test and all cores start running at 5GHz (temps max out at about 80C), everything speeds up again. The "window dragging" is now clearly crisp, same with tabs, even though all indicators say the CPU is under 100% load. But the second I stop it all slows down again. Videogame performance with this new CPU is improved where it can be, not much headroom with a 1080 Ti. So the issue seems isolated to, or at least only visible during light usage, which has me confused.

My full specs are:
CPU: i9-9900K
MB: Z390 Asrock Taichi (Bios version 4.20).
GPU: GTX 1080 Ti
RAM: 2x8GB at 3200MHz
SSD: Samsung 970 Evo
PSU: Something with 850W from Corsair, can't remember the specifics.

Any help would be much appreciated.
Possibly windows is in a lower power state so it’s dramatically down clocking the cpu so the response time is slow
 

Renegade1911

Reputable
Jan 25, 2015
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Possibly windows is in a lower power state so it’s dramatically down clocking the cpu so the response time is slow
Good catch. The PC was in Balanced power mode set in Windows 10. When I put it into High Performance, it speeds up again. The difference is clear in CPU Z. Core speeds with Balanced power are lowered, 800MHz at the lowest. At High Performance power mode they're at 4700Mhz all the time. This does fix the problem and the temps stay low, but not sure if it's desirable to have the CPU clocked to the max at all times?
 

RodroX

Notable
Aug 4, 2019
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I think, never actually tried this on a core i9 9900K, that you could go back to Balance mode, and just increase the "minimum processor state" in the Advance setting options. That way you can keep the good performance but also let the CPU to downclock a little when is not been used in high demanding tasks.

I would start with small increments, if the minimum processor state is set to 5% I will put 20%, save changes and see how it goes with the browser tabs.
 

Renegade1911

Reputable
Jan 25, 2015
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I would start with small increments, if the minimum processor state is set to 5% I will put 20%, save changes and see how it goes with the browser tabs.
Doesn't work, actually. Even at 100% minimum power state in Balanced power mode it's still slow.

Anyways, the High Performance state works fine, so thanks a lot for that!
 
Nothing wrong with Balanced Power mode that I am aware of....

My CPU (albeit an older 7700K) goes from (on assorted cores) 800 MHz to 1500 MHz, to 2200, to 4700 MHz a few times per second on normal desktop tasks...

Perhaps there is a chipset driver issue, or, some sort of botched situation exists that occurred as a result of the CPU swap.

Perhaps a by-design power limitation (that would need removed) in the BIOS is kicking in (allows full turbo for only 30 seconds, etc.) that is effectively bypassed in Performance mode?

Certainly, everyone knows Intel's 95 W TDP claims were a distant fading dream when even the 8700K came out, much less the 9900K.. (the only way to adhere to 95W average would be to downclock to 3.5 GHz or so, which some mainboards might actually do if/when desiring to adhere to assorted paper specs.
 
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