Multi Core Systems

I've heard FSX does not take advantage of multi core systems is this the case?

Also does this look like good processor for FSX?

http://www.amazon.com/Intel-i7-4790K-Processor-Cache-BX80646I74790K/dp/B00KPRWAX8/ref=sr_1_1?ie=UTF8&qid=1432274331&sr=8-1&keywords=Intel+Core+i7+4770K+%28Overclocked+4.4GHz%29+Quad+Core

It has limited support for multi-core CPUs. Basically the bulk of the processing is run on one core, while additional cores can be used for loading DEM and scenery data. This is why faster processors, especially those from Intel, are preferred over slower models with more cores.

That would be a very good CPU for FSX. As it's an unlocked K series, you could also look into overclocking for additional performance.

look into setting your affinity mask to make best use of multi core environments.

I have a quad core inel i7 3.8 Oc'd to 4.3ghz with HT. Affin' mask set to 84 in the fsx.cfg file

It has limited support for multi-core CPUs. Basically the bulk of the processing is run on one core, while additional cores can be used for loading DEM and scenery data. This is why faster processors, especially those from Intel, are preferred over slower models with more cores.

 

That would be a very good CPU for FSX. As it's an unlocked K series, you could also look into overclocking for additional performance.

I couldn't agree more. Personally, I think the 4790k is, at present, the best CPU for an essentially single-core application like FSS. Opinions, of course, vary, but I doubt you'll find anyone who is willing to say that the 4790k is a bad choice.

Doug

I've heard FSX does not take advantage of multi core systems is this the case?

This was true for the first release FSX. Since SP2/Acceleration FSX will use all cores that you configure and max them out (up to 32 or 256 that it, the info is a little unclear on that.

One thing to be aware of though: FSX is a 'visual', real time simulation. So all processes on all cores have to present their results at the same time (the 'frame'). To achieve this, a lot of checkpointing and sychronizing is necessary, that is why one 'master' core, maybe even one single thread, will always be under more pressure than the others. That is why for this type of software you not only need more cores but more power in every single one too (higher clock speed, better ALUs).

This was true for the first release FSX. Since SP2/Acceleration FSX will use all cores that you configure and max them out (up to 32 or 256 that it, the info is a little unclear on that.

 

One thing to be aware of though: FSX is a 'visual', real time simulation. So all processes on all cores have to present their results at the same time (the 'frame'). To achieve this, a lot of checkpointing and sychronizing is necessary, that is why one 'master' core, maybe even one single thread, will always be under more pressure than the others. That is why for this type of software you not only need more cores but more power in every single one too (higher clock speed, better ALUs).

This is all totally wrong. I can point out some blog posts from Phil Taylor, FSX Program leader, if you would like.

This was true for the first release FSX. Since SP2/Acceleration FSX will use all cores that you configure and max them out (up to 32 or 256 that it, the info is a little unclear on that.

The mutil-threading update to FSX only uses the additional cores for loading scenery and DEM data. Everything else, like the flight modelling, weather, AI and ATC all run in one thread on one core. Sometimes the sim will max out all cores, but typically this is only for a short time and is very dependent on what you are doing in the sim. Essentially FSX is still a single threaded application.

The mutil-threading update to FSX only uses the additional cores for loading scenery and DEM data. Everything else, like the flight modelling, weather, AI and ATC all run in one thread on one core. Sometimes the sim will max out all cores, but typically this is only for a short time and is very dependent on what you are doing in the sim. Essentially FSX is still a single threaded application.

HI, thanks - but I've been hearing/reading different opinions on this, and I don't think anyone really knows, except maybe DTG/LM. No offence. I am only describing what I can see on my own system.

But be it as it may, the fact that some work is really done in parallel is actually a good thing, whatever it is. As I said, in my opinion a software like this needs to have a master thread in any case. You can't have different modules, calculated on different cores no less, get out of sync.

HI, thanks - but I've been hearing/reading different opinions on this, and I don't think anyone really knows, except maybe DTG/LM. No offence. I am only describing what I can see on my own system.

 

But be it as it may, the fact that some work is really done in parallel is actually a good thing, whatever it is. As I said, in my opinion a software like this needs to have a master thread in any case. You can't have different modules, calculated on different cores no less, get out of sync.

Actually people do know. Phil Taylor, the FSX project lead at the time, had some good blog entries describing what the multi-threading support entailed. Pretty sure the blog entries are still available if you look for them.

A master thread is definitely required. However, in the case of FSX, it is also still running the bulk of the sim processing.

Edit: Here's the link to his blog.

http://blogs.msdn.com/b/ptaylor/

I'm not convinced, except for the master thread. It is quite obvious that most things are (have to be?) processed or at least synchronized there. But we don't know about the load those parts actually generate, maybe it is beneficial to run them in a single core or even thread. As to what gets parallel processed, I'm uncertain if this can be determined easily. I suspect you know this thread:

https://www.flightsim.com/vbfs/showthread.php?266077-How-FSX-utilizes-multi-core-processors

Excerpt:

Phil Taylor again, about FSX SP2 on 06/19/2008 (again, an excerpt)....

"The latest version of Microsoft Flight Simulator X Service Pack 2 (SP2) is a great match for the extreme multi-core processing delivered by the new 45nm Intel® CoreTM2 Extreme processors. Flight Simulator X SP2 greatly increases multicore utilization and will scale as more threads are available leading to reduced load times as well as frame rate improvements and great visual complexity during flight."

IMO it is not really worth a discussion anyway, as to me it is sufficient that the parallel workings take a sizeable amount of processing power off the "central" core/thread.

look into setting your affinity mask to make best use of multi core environments.

I have a quad core inel i7 3.8 Oc'd to 4.3ghz with HT. Affin' mask set to 84 in the fsx.cfg file

This is an old tweak that really has no effect on performance on recent processors. Older dual core processors may have benefitted from it.

TBH, any modern, mainline CPU, AMD or Intel, will run FSX well.

I guess it depends upon one's definition of "well" but to say that "any modern, mainline CPU, AMD or Intel, will run FSX well" is more than a bit of a stretch. So, since everyone is entitled to an opinion, I'll go so far as to say, using my definitions, it's just not true. But, as I said before, opinions are like belly buttons....

Doug

PS: AM tweaks still work on many modern CPU's...including my 4790K.

Intel 4790K CPU, MSI Z97 Gaming 7 mobo, Noctua NH-U12S cooler, Corsair Vengeance Pro 16GB 2133 MHz RAM, nVidia GTX 970 GPU, Cooler Master HAF 932 Tower, Thermaltake 1000W Toughpower PSU, Windows 7 Professional 64-Bit, and other stuff:

500GB SSD - Samsung 840

12TB HDD Internal - Western Digital Black

40TB HDD External - Western Digital My Book

2x Asus PA246Q ProArt 24" 1920x1200

4x Plextor PX-891SAW DVD-RW

http://www.simforums.com/forums/the-fsx-computer-system-the-bible-by-nickn_topic46211.html

"TBH, any modern, mainline CPU, AMD or Intel, will run FSX well."

I agree with this with the qualification the clock speed is still the primary governing factor. The user's expectation is another.

I'm perfectly satisfied with the 3.5GHz AMD I have considering my expectations, focus, settings, add-ons, and time/expense invested.

-Pv-

PS: AM tweaks still work on many modern CPU's...including my 4790K.

Yes, the affinitymask tweak still works, but it is probably not needed by many who apply it. FSX SP1 and later will already use as many cores as necessary on its own. The only reason to play with the affinitymask is if there are issues with FSX and other running processes on the system.

"The only reason to play with the affinitymask is if there are issues with FSX and other running processes on the system."

This is kinda vague. For many people, running FSX IS an "issue."

Active Sky Next now injects an Infinity Mask on every system it's installed on if one does not already exist. Consult Kostas if you disagree with that policy.

I'm not sure, but does Stream Edition also install a mask? My understanding is setting more than three cores is unproductive.

-Pv-

"The only reason to play with the affinitymask is if there are issues with FSX and other running processes on the system."

 

This is kinda vague. For many people, running FSX IS an "issue."

 

Active Sky Next now injects an Infinity Mask on every system it's installed on if one does not already exist. Consult Kostas if you disagree with that policy.

 

I'm not sure, but does Stream Edition also install a mask? My understanding is setting more than three cores is unproductive.

-Pv-

And NickN recommends leaving it out in his guide.

http://www.simforums.com/forums/the-fsx-computer-system-the-bible-by-nickn_topic46211.html

Personally, I go with leaving things alone unless truly needed, so I leave the affinity mask setting out (haven't seen any benefit on my systems). The only issue it really solves is when FSX and other processes are fighting over CPU core availability on the first core.

I brought it up because many seem to think you need this setting in order to enable multi-threading in FSX, which you don't. FSX will use all available cores on its own.