FYI 8600K 6 Cores, 6 Threads vs. 9900K 8 Cores, 16 Threads DOES make a difference

Long time I though (and read!) for gaming, multicore and multithread does not make much of a difference.
I upgraded a 8600K 6 Cores, 6 Threads with a 9900K 8 Cores, 16 Threads, that are about the same speed, overclock 4.8 vs turbo clock 5.0
and the loading and menus are a Lot smoother now, system more stable, less system freezes, run my parallel 50+ browser tabs now without a problem, my parallel utility programs, WMR/G2/VR more stable etc. (I also upgraded my videocard, but that is separate)

who knew …

That would make sense yes…

I hope you also updated your motherboard and did not slap that 9900k into the same board (even if it does work), the VRM’s on the board will not cope well with the 9900k and will very much cause a problem.


More cores are going to help with background (OS) tasks and indeed since SU5 some elements (glass cockpits) were given a core.

I think that the main benefit you are seeing might actually be the small instructions per cycle increase that the 9900k has over the older chip.

Even though their base clocks and turbo are the same the 9900k is capable of processing more per cycle.

Glad you are seeing better performance though.

So you upgraded your GPU at the same time…

Um, source? First, you don’t know what motherboard OP even has; it could be a $400 ultra-high-end Z390 motherboard. Second, if it was even a reasonable motherboard for the 8000 series, it will handle the 9900K just fine, especially if it’s not overclocked.

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Asrock Extreme Z370 - cheap - last generation model 1151 socket / I upgraded for the same socket & 64GB 3200 (& 12 harddisks/SSD), 9900K is on sale cheap on local Amazon netherlands 333€ (dropping still, now 300€) and these latest batches are faster at 5GHz turbo

I assumed it would be a low end board, why? because no-one will stick a 8600K in a high end board, chances of it being z370 was highly likely over z390, and a cheap one at that if budget would get a 8600k.

Just google it, its all over the net, most people will stick a fan on their VRMs because they are not designed for the power the 9900k wants, especially on cheaper boards, maybe just don’t overclock :wink:

9900k is a superb CPU though, i would say monitor your VRM temps, but cheap boards don’t have the sensors, so would have to use an external thermometer.


First thing I do is turn off hyper threading on my 9900k?

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Me too. Mine performs pretty much the same, but much cooler, dropping from 20 to 10 threads with my 10850K by turning HT off. Running FS + VR (WMR) + addons + browser + twitch + discord + anything else runs at about 30-40% average core load, so still plenty of headroom.

Why buy a hyper threading CPU and then turn it off.

Why not buy an i7-9700K that does not not have hyper?

Little more cache, a warmer room in winter?

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I had to buy a pre-built system to get my 3080 and it came with an i9 10850K. I would have been happy with an i7 or even a high core clock i5. So I tried running my system with HT off and, not only did it overclock higher and run cooler but doesn’t really affect gaming performance at all.

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I would do it if I were you. I get more performance in games with no very good hyperthreading (simulators). You get more performance than with HT on. It is my experience.

Well, you can turn it on for rendering video and other kind of software.


I actually began a comparison where all I changed was Hyperthreading and V-TD, gorgeous day here so I left realtime weather on not really thinking it through …

1st flight, clearing skies … maybe it’s a little behind from earlier, well it can only get better?

system hardlock … expected, still running 5ghz all cores locked, I got a few screens of performance so march on

2nd flight, thunder lightning 500 yrds visibility, rain entire test ruined


Feels like 74°F Humidity: 64%
Dew point: 59°F

Winds: E, 3 mph
Visibility: 10 mi
Precipitation: 0 in

FU FS just FU

I have two machines, one with an 8800K and one with a 9900 K .

The 8800K has an 1080TI and the 9900K has a RTX 2080 TI.

Both machines are OC to 5.2 GHZ.

I can not make any discernible difference between the two in FPS in a practical sense .

However when I turn off hyperthreading on the 9900K and limit it to 8 cores I can run it at 5.3Ghz and that makes a huge difference.

Moral of the story? MSFS is CPU bound and hardly uses more than 4 cores and still mostly 1 core.

The GPU clearly still makes little or no difference due to the legacy Graphics API in use and the fact MSFS is still CPU Bound.

(Why two machines? I keep one at work for my pleasure.)

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Because with Hyperthreading turned off the CPU runs cooler and I can oc to 5.3 GHZ from 5.2 with HT and it is even more stable than 5.2.

If you think MSFS doesn’t run better with more GHZ and makes practical use of more than 4 cores then you are on your own.

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