Yes, you don't essentially need an AM with HT Off and 4 cores.

@WebMaximus,

        Please keep us posted on the new performance - was it difficult to get 4.7Ghz? What memory and timing did you use?

It would be great if you can provide some comparison to your old system and maybe just provide an FPS check with the default scene but with unlimited set instead of 20fps limit. Once you get your addons loaded and settings the way you want them, it is difficult to compare. You might be the first to report P3D results with a 6000 series i7.\

 

Thanks!!

 

Dave

 

Hi there Dave!

 

As promised I've now checked the FPS right after a 100% fresh P3Dv2.5 installation. Haven't changed a thing but set the FPS to unlimited, just fired it up and sitting in the v/c in the default startup scene the FPS jumps up and down quite a bit but mostly it seems to stay at around 88-102 FPS.

 

No clue if this is good or bad, the real test for me will be when I install all my regular add-ons.

 

Should also add that this is with the 6700K running at 4.6 GHz and with HT enabled but no AM set in Prepar3D.cfg.

 

My MSI GTX 980Ti Gaming G6 is slightly overclocked, increased both GPU and memory by 100MHz but stock voltage.

 

The resolution is 3840x2160.

Hello !

For me now,  AM or not it's the same.

And HT off @ 4.9 Ghz is better than HTon @ 4.4 Ghz

Hello !

For me now,  AM or not it's the same.

And HT off @ 4.9 Ghz is better than HTon @ 4.4 Ghz

Thanks for sharing. 4.9GHz with 12% extra over 4.4GHz running the main sim thread will definitely bring higher fps. Still possibly could be a better tradeoff even against the far slicker multi threading of HT=On.

 

However, on an HT enabled setup the AM will make a difference if it prevents two main threads running on the same core, since by definition they share throughput. P3D is difficult to check accurately for performance, but I've written tools to do it, to save the guesswork.

"However, on an HT enabled setup the AM will make a difference if it prevents two main threads running on the same core, since by definition they share throughput. P3D is difficult to check accurately for performance, but I've written tools to do it, to save the guesswork."

 

HT means a physical core is allowed to be used when not in use.... so the througput is not doubled but somehow improved (due to swapping ), so having two threads running in a "HT Core" wont reduce the ability of the core to run at its max performance for each thread, therefore as it is working for a larger % of the available time (you will notice also a temp increase) the througput is increased, off course depending on the way the program was optimized for MT allowing the OS to make use of it.....

 

Jorge

No. HT means a physical core is presented as two logical processors to the o/s. This way the core can be designed to swap threads more efficiently than if run on one single threaded physical core. Say you have two identical threads demanding 100%. When they run on one single threaded core, they get use of 50% throughput each through timeslicing, the jobscheduler decides how long each timeslice should be, so what? Well, the mechanism of saving and reloading the state of each thread is vastly improved with HT enabled, but the core is presented as two logical processors to the o/s. The two threads appear to run on their own processor. But as is explained, those two logical processors are actually emulated by one physical core for the purpose of improving the switching. So when we start our simulator on an HT enabled system, we want to ensure our main thread gets the core all to itself, and not share it with the second major thread by masking off one LP of the first core presented to the sim, the second thread is started one LP along, which will be on the next core.

At the OS level yes , but the actual processor  ( HT Core) operates the way I described it.

 

Jorge

I get you when you say "having two threads running in a "HT Core" wont reduce the ability of the core to run at its max performance for each thread", if you are saying an HT core can switch two threads without penalty, that's what I'm saying, but to do that it presents the core as two LPs. But when you say "HT means a physical core is allowed to be used when not in use", I don't understand what you are saying there. Two threads run without penalty of switching, and appear to run on separate logical processors, that's HT in a nutshell. How LPs are selected and distributed amongst processes is up to the jobscheduler, but a program can intervene if deliberately programmed to do so.

If a thread  is running in a Core that is MT, when the thread stops (request  I/O or  Graphics) the core stops that thread , swaps and  is available for work, if theri is no MT the core will sit there waiting for the request to return. Again this is not the way the OS works it is the actual processor chip.

 

I think that also we are considering that the program (P3D) is a MT program .... I understand your background is SW ...mine is HW

 

Jorge

Was it ever confirmed P3D indeed is a MT software and thus will benefit from having HT enabled?

Thanks for sharing. 4.9GHz with 12% extra over 4.4GHz running the main sim thread will definitely bring higher fps. Still possibly could be a better tradeoff even against the far slicker multi threading of HT=On.

 

However, on an HT enabled setup the AM will make a difference if it prevents two main threads running on the same core, since by definition they share throughput. P3D is difficult to check accurately for performance, but I've written tools to do it, to save the guesswork.

I will try with  the AM more seriously...

I'm only looking at fps and not the smooth of the sim... 

I will look that too...

If a thread  is running in a Core that is MT, when the thread stops (request  I/O or  Graphics) the core stops that thread , swaps and  is available for work, if theri is no MT the core will sit there waiting for the request to return. Again this is not the way the OS works it is the actual processor chip.

 

I think that also we are considering that the program (P3D) is a MT program .... I understand your background is SW ...mine is HW

 

Jorge

So are you trying to say I have somehow explained something wrong somewhere or what?

 

 

Was it ever confirmed P3D indeed is a MT software and thus will benefit from having HT enabled?

P3D is a multi threaded app, has a main thread, pooling thread, and threads that collect data, and is running on highly multi threaded subsystems. The machine or o/s benefits from HT, the sim fps benefits from GHz.

So with that said you suggest trying to get the highest GHz and as a result FPS is preferable when your main goal is to make P3D perform at its best?

So with that said you suggest trying to get the highest GHz and as a result FPS is preferable when your main goal is to make P3D perform at its best?

No I didn't say that. I said "The machine or o/s benefits from HT, the sim fps benefits from GHz." It's up to you if you want to gain a few more MHz and hence fps from turning off HT, you may find less smoothness overall in the PC without HT.

No I didn't say that. I said "The machine or o/s benefits from HT, the sim fps benefits from GHz." It's up to you if you want to gain a few more MHz and hence fps from turning off HT, you may find less smoothness overall in the PC without HT.

 

What I meant was that you might prefer to do whatever you can to give P3D what it needs most rather than giving the OS the same thing but I realize just like you say and as I said myself previously that high FPS doesn't necessarily equal to smooth performance.

 

Guess the only real way to tell for sure is to try both approaches and then pick the one that works best for you.