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Hyperthreading and performance.


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The problem is that hyperthreading gives you only 40% or so of a CPU. However, operating systems are supposed to use the real CPUs first and only then go to the faked ones. Windows does have issues with that from time to time. The small freezes are surprising and sound like another mess-up by Microsoft. I take it this is on Windows? Is your system patched to the current level?

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33 minutes ago, Gurgel said:

The problem is that hyperthreading gives you only 40% or so of a CPU. However, operating systems are supposed to use the real CPUs first and only then go to the faked ones. Windows does have issues with that from time to time. The small freezes are surprising and sound like another mess-up by Microsoft. I take it this is on Windows? Is your system patched to the current level?

It is windows 10. It is ~2-3 weeks behind on updates though. I should also say the performance gains in fps are small. However it completely eliminates dupes freeing in place for a second while the game struggles to assign them a task.

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9 hours ago, Cursed_Handus said:

It is windows 10. It is ~2-3 weeks behind on updates though. I should also say the performance gains in fps are small. However it completely eliminates dupes freeing in place for a second while the game struggles to assign them a task.

2-3 Weeks on updates should not do this. How much memory do you have? The freezes may be garbage collections. In that case they should have happened with hyperthreading on as well though.

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The games min spec and compute design is currently 2 cores - The more computer power gets allocated and performed by 2 cores, the better for the game. Hyperthreading are virtual cores which "split up" the compute power of the physical cores.

If one could dangle all existing physical cores together to be 2 physical cores, by "sticking" them together :D ...The ONi would run best.

If one runs the game on a 100 core system, one can expect 2% calculation power for the ONi game to be available.

Superfast 2 core system = ONI win win plutonium killer bee beeta

@Cursed_Handus

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FYI

Some good posts, how I find, on Hyperthreading can be found below in the links. The game runs best on fast performing single thread cpu`s. Here is also my classic link on fast single thread performing cpu`s:

https://www.cpubenchmark.net/singleThread.html

Anything which can be modified on a system to increase single thread performance will raise the games fps.

---------

https://www.quora.com/Does-turning-off-hyperthreading-increase-FPS

Quote:

Daniele Paolo Scarpazza, a computer scientist working in High-Performance Computing.

In most cases, yes.

How much, depends on the workload and instruction mix.

Hyperthreading may improve aggregate performance over multiple threads and, of course, can not improve single-thread performance.

In most cases it improves aggregate performance at the expenses of single-thread performance.

If the applications you are running are reasonably well optimized (high arithmetic intensity and good cache locality), you will see a decrease in performance by enabling hyperthreading.

This is pretty obvious, when you think about it. You are comparing the following two scenarios:

  • without hyperthreading, assuming no oversubscription of threads to cores: each thread has all the resources of a core, especially the L1 and L2 caches, available for itself, undisturbed. Also, in absence of spurious events, you'll see zero context switches and pay zero context switch overheads;
  • with hyperthreading, assuming 1:1 subscription of software threads to hardware threads (i.e., a 2:1 oversubscription of software threads to cores), you now have two threads contending for the the same L1 and L2 caches and other common on-core resources. In addition to that, you'll pay for context switch overheads between the two threads. Switching contexts between the on-core threads is not as expensive as an OS context switch, but it does not cost zero."
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Nice post bubba, there’s so much misinformation about hyperthreading (smt), this one is spot on. 
 

my 2ct, you may improve single thread performance slightly by turning it off, but you will get a substantial multi thread performance hit. So in most modern applications (which use many threads) it’s better to have it on, For ONI you may see a few % gain, probably not noticeable.

Hyper threading pays dividends when a thread is waiting for data from the memory (which can take up to 100 cycles), During the stall, the 2nd thread can use the resources.

If you could switch it on and off from windows, I would probably do so while playing ONI, but to reboot for it is too much hassle for too little payoff 

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FYI

Most games run single threaded - I`m playing WorldOfWarships right now, same story. On Intel cpu`s a lot of games perform so much better with deactivated HyperThreading.

ONI depends a lot on cpu caches, the sharing of those with HT switched on... can drag the fps down strongly.

On my heavy load game saves, dlc classic terra map, switched off HT improves the ONI game speed by ~30% with the i7 7700k, 1kg air cooler on top + metal paste, board laying around/no pc case + 20% turbo mode core single core overclocking.

Total improvement of my system is ~40% more fps compared to a standard cooled stock Hyperthreading-on system. :rolleyes:

One does not have to spend much monies, its investing some time and knowledge in to things.

I find cpu`s with 4 high performing cores, with dedicated fat cpu caches, best for game recording/streaming whatever. Would always prefer to setup a tuned top performing 4 core system with fat cpu caches than running a stock default 16 core system for anything related with gaming.

Shame they don`t do 2 core`s anymore, AMD could make monies and brand fame with with a monster 2 core cpu for hardcore gamers.

A new built ONI system for me will be a tuned 4 core in the next year or so, with monster size l1/l2/l3 core caches and fastest default GHz + good turbo on single core...Either AMD or, if Intel gets further price bashed by AMD, a tuned Intel system :congratulatory:

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