Turning off hyper-threading had quite an impact on my P3Dv5

[adam77 63]

I know this is an old post, yet the topic has been raging for years. 

From what I can read, no one seems to know how to use Hyperthreading properly on their PC unless it was set up from the manufacturer. 

 

I can confirm, Hyperthreading set to ON will boost performance for P3Dv5.3 IF (big if) it is set up correctly in Windows and P3D. Otherwise, it will actually hinder the performance. 

 

NO OTHER APPS OR PROGRAMS ARE NEEDED TO MICROMANAGE THE CPU IN CURRENT WINDOWS 10.

 

My PC specs are 

 

CPU: i7700k (not overclocked, boosted to 4.60Ghz) running at 35-60% usage

GPU: 1080Ti running at 80% to 100% usage

RAM: 32G running at 3200Hhz

 

The reason for everyone not having joy with HT turned ON in the BIOS. Is because Windows is still running in the mode of using physcial cores only and parking non active cores (the virtual ones) meaning P3D can only access now HALF of the available CPU.. which isnt good, although current P3D uses more of the GPU thankfully than the CPU, but then if the GPU isnt set up to schedule half the jobs for P3D, the CPU will do it (plus it depends on how youve set up your P3D in terms of whats using the CPU and whats using the GPU) which doesnt help if only half of your CPU is being allowed to be used. 

In P3Dv5.3 I get between 40-60fps (depending on the plane and location) and I run ALOT of addons, including heavy planes. The addons you use will also have an effect as alot of (so called compatible for v5) addons still use alot the CPU. I can confirm HT is better turned ON than OFF and here is why. 

 

Lets say you have 8 cores on your CPU, thats 8 threads that can dish out jobs. Yet the CPU can be run to have 16 threads (more workers) to complete more jobs. 

Hyperthreading splits a single core into two and creates a virtual core and allows you to have two threads instead of one. Programs and processes access these threads to get the job done, so by having more threads at work, you can get more work done. 

 

So by having Hyperthreading turned OFF you are effectively only using HALF of your CPU. Turn it on, double the thread count and you are now using the full potential of the CPU. 

IF WINDOWS IS SET UP TO DO THIS. By default, Windows will only use the physical cores of your CPU, so if HT is OFF, you are only using physical cores. 

When you activate HT in the BIOS, windows only uses half of your CPU.. word not allowed! 

By default, Windows does not give you the full control within the backend to set the PC up as a full flight sim PC to fully take advantage of your CPU and GPU. They probably dont want people starting fires in their homes by using 100% of the GPU and CPU which will raise the inner temps of the PC. 

Firstly, you need to unlock the FULL control panel available for the POWER PLAN in the backend. I have reg keys in my discord that do this. 

Once you have full access to the Power Plans Power Options. 

You need to head into the Power Options within the control panel and into the Power Plan you are using (hopefully not the balanced recommended one) and set how much of the CPU to use in the Power Management section of the power plan. 95-99% is good, never 100%. Also you can disable the parking feature if you dont want the CPU going to sleep on the cores if they dont get used. You can set up windows here to park unused cores so you dont burn out your CPU, but this is tricky to do and can have reverse affects if not done right, but this is basically what Process Lasso will do for your programs and cpu on the fly. Process Lasso is a program that no longer needs to be done, because you can do it for yourself and then not have that PL process taking performance away from the sim when its used. 

 

Once youve configured the CPU to be used FULLY and you have HT turned ON in the BIOS. Make sure you have GPU scheduling turned ON in the backend of Windows and set to the configured Power Plan for P3D to activate your CPU and GPU when flying to get the most out of it, the final step is too set the affinity mask correctly and P3D doesnt do it correctly by default. You want to set your affinity mask by using this calculator : http://izn-flightsim.s3-website-us-east-1.amazonaws.com/affinity.html#presetAnchor type how many cores and logical processors you are using and click START BUILDING and then click the yellow FIRST CORE FREE button to give you an accurate affinity mask number, copy these into the P3D.cfg file and 

 and NOW you are using your hardware fully.... 

You will find improved performance in the sim with addons. 

I MADE 3 VIDEOS ON MY YOU TUBE CHANNEL TO FULLY EXPLAIN THIS ON HOW TO DO IT AND IT INCREASED PERFORMANCE IN P3D BY QUITE ALOT. As seen in other videos. 

 

In P3D, disable all AA in the menu and set it in the GPU to override and set it for the GPU. Also, turn VSYNC OFF in the p3d menu and get the GPU to lock your fps in the Nvidia Control Panel... 

Edited September 23, 2022 by adam77

[simfan1983 185]

I agree with most of your post but not this bit:
"NO OTHER APPS OR PROGRAMS ARE NEEDED TO MICROMANAGE THE CPU IN CURRENT WINDOWS 10."
I find Process Lasso incredibly useful and effective in managing core usage and also setting priorities. It shows we what is going on and I can easily restrict apps to use non P3D cores. With the FSLAbs I have all the cores sharing the load and this helps reduce any stutters etc.

I'm using Windows 11 not 10 but I think the same principles apply - turn HT on, use affinity mask to select where P3D does its work and exclude certain cores and then us PL to require apps to use those non P3D cores.

[adam77 63]

45 minutes ago, simfan1983 said:

I agree with most of your post but not this bit:
"NO OTHER APPS OR PROGRAMS ARE NEEDED TO MICROMANAGE THE CPU IN CURRENT WINDOWS 10."
I find Process Lasso incredibly useful and effective in managing core usage and also setting priorities. It shows we what is going on and I can easily restrict apps to use non P3D cores. With the FSLAbs I have all the cores sharing the load and this helps reduce any stutters etc.

I'm using Windows 11 not 10 but I think the same principles apply - turn HT on, use affinity mask to select where P3D does its work and exclude certain cores and then us PL to require apps to use those non P3D cores.

Everything in Process Lasso can now manually be set up in P3D and Windows. It really is a waste of resources now to get someone else to do it during flight sim... 

[IanHarrison 522]

I have reg keys in my discord that do this. 

Where do we find this?

[adam77 63]

7 minutes ago, IanHarrison said:

I have reg keys in my discord that do this. 

Where do we find this?

In the free flight sim assets channel.. you can find the discord invite link on any one of my videos on You Tube

[d.tsakiris 418]

2 hours ago, adam77 said:

So by having Hyperthreading turned OFF you are effectively only using HALF of your CPU

I don't think that's true. HT (or SMT for AMD CPUs), as far as I understand, optimizes compute power in certain situations - namely when a process on a physical core is waiting for data to be fetched from cache, RAM or disk. Then the CPU will switch to the other, virtual core and continue working on processes there that already have fetched the data they need, instead of just waiting (and of course the other way around). So, I believe using HT/SMT can turn out to be more like halving your cores, as the situation can arise where processes will “fight“ for computing resources. The question is: Which type of processes are flight simulators? I'd say the latter type, as I regularly see P3D maxing out the the cores it's using.

I'd say it depends on how many cores your CPU has. With CPUs with more cores - say: 8 or more - I think you're better off without virtual cores. With less cores, it might be smart to utilise H/SMT for the scenery threads, but I'd make sure to keep other processes away from the cores running P3D's main thread(s).

[Bob Scott 7,721]

2 hours ago, adam77 said:

Hyperthreading splits a single core into two and creates a virtual core and allows you to have two threads instead of one. Programs and processes access these threads to get the job done, so by having more threads at work, you can get more work done. 

So by having Hyperthreading turned OFF you are effectively only using HALF of your CPU. Turn it on, double the thread count and you are now using the full potential of the CPU.

If only it were that simple.

Hyperthreading maintains two separate instruction "contexts" (aka virtual CPU/vCPU) on each physical CPU core.  But there still is just one physical core being shared--only one of the two virtual CPUs can process instructions on the shared processing unit at a time, so if one of the threads is an especially high duty-cycle process (e.g. P3D's main thread), sharing that core with another thread slows down execution of the all-important main thread whenever the core's processing is diverted to another thread running on the shared virtual CPU.  Sharing the main thread's core also reduces the amount of super-fast cache memory available to the main thread, because HT will split the available cache between the two vCPUs.

Turning HT off (or masking one of the virtual CPUs on the core running the main thread) permits the main thread to run without competing with other threads for the resources of that core, which reduces thread locking/wait times across the other dependent threads running on the other processors.

I've done extensive testing on this myself, and P3D is noticeably smoother when the main thread is not run on an HT shared core.  In fact, on my 10-core 10900K, I found no discernible benefit from running HT at all, but with it off, I am able to clock the CPU 200MHz faster due to less heat dissipation.

HT allows an increase in throughput in many scenarios, *not* because it doubles the number of running threads--an 8-core CPU can only run 8 threads at any given moment because there are still only 8 processing units.  HT permits faster switching between threads by keeping a separate instruction pipeline and memory cache that doesn't need to be swapped out to/from RAM in order to run.  That's great in most scenarios, but not so much in a real-time application like a simulator that is greatly dependent on a single main thread as the arbiter of the application's other activity across the rest of the processing space.

 

[Ray Proudfoot 8,962]

3 hours ago, simfan1983 said:

I have an i7 8700K o/c to about 4.4 GHz

My i7-8086K is effectively the same CPU. Using the Asus utility available on their website - Ai Suite - I have managed to get the first 3 cores running at 5.0 and the remaining 3 at 4.9. There is a considerable uplift in performance.

I used to shy away from overclocking but this utility does it all for you. The only proviso is the need for an Asus mobo.

https://www.asus.com/support/FAQ/1012780/

[simfan1983 185]

2 hours ago, Ray Proudfoot said:

I have managed to get the first 3 cores running at 5.0 and the remaining 3 at 4.9

I don't have enough cooling to get that amount of CPU overclock. If I push above 4.5 the core temps go into the 80s and I'm not comfortable with that. I could try reducing the voltage a bit but I'm happy with all cores working away at 50-95% capacity and 4.5. I do have an Asus MB but haven't used AI Suite for many years as my previous experience with it wasn't good. Maybe I should give it another try. I find some of the Asus software to be incredibly bloated and anyway I'm happy making changes in the BIOS myself. Asus Armoury Crate is absolute rubbish for example! I do however use the GPU Tweak software to o/c the GTI 1080 Ti and I o/c the ram and CPU in BIOS.

The main issue I had with P3D was that a recent Windows 11 update installed something for Office 365 which conflicted with the PMDG use of Access for RAAS. I spent ages trying to solve the issue and eventually identified the problem and had to uninstall Office 365 completely and then reinstall the AccessDatabaseEngine_x64. WIthout the Access engine P3D would not launch. Now everything seems to be working well thank goodness. Having completed a 12 hour long haul yesterday while online with Vatsim with no problems I can get back into flying and not problem solving! 

Edited September 23, 2022 by simfan1983

[Ray Proudfoot 8,962]

6 minutes ago, simfan1983 said:

I don't have enough cooling to get that amount of CPU overclock. If I push above 4.5 the core temps go into the 80s and I'm not comfortable with that.

Fair enough. I have water cooling and together with better fan management it copes well.

I ignored the bloatware with AI Suite and just installed the required program. Each to their own. 👍

[TurboKen 221]

49 minutes ago, simfan1983 said:

 Having completed a 12 hour long haul yesterday while online with Vatsim with no problems I can get back into flying and not problem solving! 

Did you start the flight and then go to work, and finish up the flight when you got home? 12 hours is a LONG flight.

[simfan1983 185]

24 minutes ago, TurboKen said:

Did you start the flight and then go to work, and finish up the flight when you got home? 12 hours is a LONG flight.

No Sir, I was flying with someone else who was streaming on Twitch and just had a short break for food. It was actually very rewarding - Hong Kong to Zurich in a Swiss 777 flying an IVAO tour flight. I love long hauls, especially when P3D doesn't CTD!

[Rogen 1,091]

Interesting topic.

I have SMT set as disabled (SMT= the AMD version of HT) as it allows a higher overclock rate while still keeping the temps at a managable level.

Given I've 8 cores with SMT off it's no big deal as there are more than enough cores to do the job in this instance.

The CPU is an AMD Ryzen 5800x and I have trialled using all 16 cores/threads, different affinity masking and various overclocking levels, where the best result has been SMT=off allowing a higher overclock and subsequently better performance. Yes it's a few points down on CPU benchmarking for apps that drive all cores to max, however for P3D the higher clock speed does equal better performance.

CPU overclock tuning involved first running the AMD Ryzen Master CPU utility to understand which were the fastest cores and to also understand the sort of max temps Ryzen Master would push to with safety in mind, which turned out to be 90 degrees C.

With the above info I used an affinity mask to put the main thread on core #3 (being the fastest) and then Process Lasso to set P3D to use all cores, result is main thread on fastest core while still using all cores.

Then it was a matter of slowly increasing the core speeds and with a slight increase in voltage I've managed to achieve a stable 4.8 Ghz while just touching the max temp on only the very heaviest use occasions.

Cooling the CPU is of great importance and I use a Noctua NH-D15 SE-AM4 which is super quiet while providing fantastic cooling, if it wasn't for the Noctua I certainly would not have been able to achieve the overclock that I have.

Cheers

[adam77 63]

Overclocking in Flight Simulation I would say is never recommended. You can in games where the overclock runs for short bursts of time, but over many hours of flying where the CPU would be pushed anyways, I would say you are getting the CPU to sprint for too long a period and over time, shorten its lifespan. I suppose with the way CPUs are released, it doesnt matter as you can always buy a new one when youve burnt through the current one. I just never find it worth it for the performance gain in the long run. 

[Rogen 1,091]

1 hour ago, adam77 said:

Overclocking in Flight Simulation I would say is never recommended. You can in games where the overclock runs for short bursts of time, but over many hours of flying where the CPU would be pushed anyways, I would say you are getting the CPU to sprint for too long a period and over time, shorten its lifespan. I suppose with the way CPUs are released, it doesnt matter as you can always buy a new one when youve burnt through the current one. I just never find it worth it for the performance gain in the long run. 

Heh, cannot say I've ever burned through a CPU as yet and I've overclocked all my CPUs for the past 10 years.

In actuality my first overclock was an Amiga 68060 CPU, of course those were Mhz days and an oscillator crystal had to be replaced to overclock, not the Ghz BIOS based OC like we have now.

The trick is to not overdo it, keep an eye on the temps while trialling the overclock and gradual is the way.

I'm waiting for the new AMD Ryzen 7000 series to drop with their 5.5+ Ghz speeds, not too long to wait now 🙂

Plus the new 4000 series Nvidia GPUs are just around the corner, should be a potent match.

Cheers

 

Edited September 24, 2022 by Rogen