PSA: if you have an Intel processor with 8+ cores disable Hyperthreading [Updated]

User Support Hub Hardware & Peripherals
1

I have been benchmarking and testing several tweaks to improve the performance and one of the best FPS boosts for me (after overclocking) was to disable Hyperthreading technology on my CPU.

Disclaimer: This might make your performance worse if your CPU does not have at least 8 physical cores and if it’s not overclocked.

My PC specs:

CPU: 10900KF @5100 MHZ, 1.30v, LLC 7
GPU: RTX 3090 Tuf OC, undervolted @0.875v
RAM: 64 RAM @3600MHZ CL18
Mother Board: Asus Maximus XII Apex
Watercooler: Corsair H150i pro RGB
Monitor Resolution: 3440 x 1440

Test methodology:

Plane: Beechcraft Baron G58
Multiplayer and Live traffic off
Weather and time: Scatterad Clouds & 12:00 PM
Flight plan: Takeoff from New Wark Liberty International → Statue of Liberty → Empire State → back to New Wark
The total time for benchmarking for me was: 9 minutes 32 seconds
Used MSI Afterburner Benchmark feature for measuring

I have chosen New York City for the test as it is still one of the most demanding cities in the SIM.

Screenshot 2021-06-25 121806
Screenshot 2021-06-25 1218062769×1412 167 KB

Screenshot 2021-06-25 121844
Screenshot 2021-06-25 1218442612×1324 229 KB

My settings:

settings
settings2467×1096 179 KB

settings2
settings22461×1085 187 KB

settings3
settings32462×1085 188 KB

Results: (Update IV)

With Hyperthreading enabled:

23-06-2021, 23:39:58 FlightSimulator.exe benchmark completed, 19608 frames rendered in 589.719 s 
Average framerate  :   33.2 FPS
Minimum framerate  :   22.2 FPS
Maximum framerate  :   42.5 FPS
1% low framerate   :   18.1 FPS
0.1% low framerate :    8.2 FPS

With Hyperthreading disabled:

24-06-2021, 00:16:42 FlightSimulator.exe benchmark completed, 22735 frames rendered in 573.015 s
Average framerate  :   39.6 FPS
Minimum framerate  :   26.0 FPS
Maximum framerate  :   54.5 FPS
1% low framerate   :   21.0 FPS
0.1% low framerate :    8.9 FPS

Results: (Update V with Hotfix 1.18.15.0)

With Hyperthreading enabled:

07-08-2021, 17:59:31 FlightSimulator.exe benchmark completed, 38359 frames rendered in 573.047 s
                     Average framerate  :   66.9 FPS
                     Minimum framerate  :   28.6 FPS
                     Maximum framerate  :   80.1 FPS
                     1% low framerate   :   42.8 FPS
                     0.1% low framerate :   11.4 FPS

With Hyperthreading disabled:

07-08-2021, 18:17:13 FlightSimulator.exe benchmark completed, 39846 frames rendered in 575.532 s
                     Average framerate  :   69.2 FPS
                     Minimum framerate  :   24.5 FPS
                     Maximum framerate  :   81.4 FPS
                     1% low framerate   :   37.6 FPS
                     0.1% low framerate :   10.0 FPS

Conclusion: Even after update V having HT disabled still gave me more average FPS and a smoother experience with less stutters (they are more perceptible now with higher FPS).

6 Likes
2

I think this need to made clear between disabling “HyperThreading” or “Virtualization Technology, or HyperV”.

I experienced increase in FPS and much smoother flight, while having HyperThreading ON, but Virtualization and HyperV OFF.

And I’m on i9-9900K Stock speed.

2 Likes
3

This is for Hyperthreading technology specifically and if and only if you are overclocking. You will probably have a significant FPS boost if you overclock your CPU to 5GHZ with disabled Hyperthreading.

4

Okay cool… I don’t like overclocking, so I’ll just keep it as is.

1 Like
5

There was a thread on this a while ago, it definitely works. I’ve an i9-10940 with 14 cores overclocked to 4.7ghz. Disabling both hyperthreading and virtualisation has made a huge difference to my FPS’s and also eliminated all stutters.

1 Like
6

Very Interesting and might explain why, when I see numerous posts from folks with more powerful CPUs than mine, I question why they seem to be having worse performance than I do. Based on what you’re saying it could be because of the specific CPU I have. I have an Intel i9700k, which does NOT support hyperthreading by design. Currently I can lock my frames at 30, no stuttering, and most of my settings are Ultra. I have an RTX2070 @ 1440 which is also giving great performance.

2 Likes
7

Yes, also you can have some interesting boost in FPS by overclocking your CPU even in small amounts like +100MHZ on each core (as long as you have the thermals required for doing so).

→ speculation ←
From the empirical data I got in my tests MSFS 2020 benefits a lot from multi-threads up to a certain point, after that point (depending on your clock speed) more threads will actually create an overhead that degrades your performance.
I tested this hypothesis in two processors i9 9900K and now the 10900KF with around +6 FPS across the board when combining:

  1. high single core speed (5GHz or more)

  2. disabled Hyperthreading

So in my case 8/10 overclocked cores without Hyperthreading performed better than the same parameters with Hyperthreading.

I even believe that you don’t need to overclock all your cores to get this result but just the specific core where the mainthread runs (you can notice this by observing the high utilization).
→ end of speculation ←

8

I have the same. Performance is better with HT disabled. See my post some months ago: https://forums.flightsimulator.com/t/performance-degradation-at-lytv-even-with-latest-patch-1-14-6-0/385460
It might be caused by msfs thread design. If one single main thread is heavily loaded, it is better to disable HT and give this thread a complete core and a little bit more headroom.
Maybe things change with the coming DX12 implementation.

1 Like
9

I9 10850k (10cores), with HT off, i didn’t really have more FPS, but no more stuttering (and CPU temp is less than with HT on).
Virtualization off/on didn’t change anything (and i don’t see why it did).

10

Same mate.
i9 9900KF

11

Do you have any overclock? As I said in the disclaimer this doesn’t apply for stock configuration.

Edit: If you don’t have any overclock you should consider, the 9900KF is a great CPU for overclocking. Most can easily reach 4.9 without much effort.

12

Yep.
@4.8 offset -0.035v, vcore max 1.280v LLC 4

13

Got it, you are in the range where the clock speed is not high enough so Hyperthreading is probably helping you.
With this processor you can most certainly reach 5GHz depending on your cooler. I got a good +6 to 10 FPS going from 4.8 to 5GHZ without HT on my 9900K (1.33 LL7). CPU overclocking is by far the tweak that gives you the best performance improvements in this SIM

14

Nope, with HT on no need @5GHz in my case :wink:

I know how to OC my gaming rig mate :wink:

With HT off I can OC without any problems to @5GHz all cores

In my case better is HT ON and @4.8GHz or @4.9GHz

15

Out of interest have you made any comparisons with any other games with hyperthreading on or off?
I play other games so don’t want to keep switching between on and off if it has a negative effect for other games.

16

No I did not test in other games having HT off, as a rule of thumb if the game is not a simulator you should probably keep HT enabled, if the other game is also a simulator you could test with it off. In my case I’ve crated 2 profiles on my motherboard so it is pretty easy to change.

1 Like
17

Interesting, are you using VR?

18

Ok thanks for that info.
Well I just tried msfs with HT disabled and it does appear after comparing in all the exact same conditions that it does indeed increase performance wasn’t a huge change in fps but i notice the main thread timing was lower by as much as 4.0ms and ram usage was slightly increased though could be that camera wasn’t in 100% the exact same spot. The sim did also seem a little smoother.
Guess if I know I’m gonna be using msfs it’s not much hassle to disable hyperthreading before start up.

19

Interesting, I have just tried disabling HT and did not find any impact, with a similar system:

10850k at 5.1ghz all cores, -0.05v offset
Zotac 3090 at 1900mhz 0.875v
32gb 3200 RAM at 3600 16/20/20/20

However unlike the other poster I don’t understand the CPU overclocking, ie my LLC and most other things I do not understand so are left at auto. Is there anything else I should be changing and if so could you recommend me anywhere I can learn further about this topic?

1 Like
20

Nope:

  • MSI Z370 Tomahawk
    • BIOS 7B47v1B2
    • HT - ON
    • HPET - OFF // in system - Disabled
    • Virtualization - OFF
    • Security Device Support - Disabled // waiting for Windows 11 :smiley:
    • Above 4G memory/ Crypto Currency mining - Disabled
  • MSI MPG A850GF 80 Plus Gold 850W
  • Intel i9 9900KF
  • NZXT Kraken Z63
  • 32GB ram 3200MHz (4x8GB)
  • MSI RTX 2080 Super Gaming X Trio
  • Sound Blaster Z
  • X56 H.O.T.A.S
  • TCA Sidestick Airbus Edition
  • 2x NVMe M.2 Samsung 970 Evo (250GB and 1TB)
  • 3x SSD SATA III

Worth trying Disabling HPET in BIOS and system via CMD command.
// By default in BIOS HPET is Enabled
// HPET Enabled can be the reason of stutter, microstutter, high CPU loads etc.
// Disabling or Enabling it can have different effects per system.

1 Like