FSX Multi-Core Capability

[Mickey_Techy]

With release of SP2, Microsoft had claimed to have provided 'multi-core capability' to FSX.

I am running my computer with a Core i7-920 processor. But, with FSX running, when I look in the Task Manager, I notice that Core#1 is maxed out at 100%, core#2 is generally pushing between 45 - 65%, while all other cores (#3 till 8 ) do not show any activity at all.

This at a time, when FSX is already struggling to push the frame rates.

Have I got my FSX setup incorrectly? Am I doing something wrong?

I was speaking about this issue with another friend, and he told me that FSX is a 'single thread application' and can not utilize the multiple core's of a processor.

What is the correct 'zing-bang' on multi-core capability of FSX?

Is there anyone, who has faced a similar issue or has a solution to the same?

Thanks in advance.

Mickey

[SpazSinbad]

MT, interesting, thanks. Here is something found just now (no time to read it all just yet):

http://software.intel.com/en-us/articles/microsoft-flight-simulator-x-soars-to-new-heights-with-multi-threading/

Sadly this post is missing: http://blogs.msdn.com/b/ptaylor/archive/2007/07/03/fsx-sp1-the-blog-posts.aspx

[Mickey_Techy]

Thx for the Link Sinbad,

As far as practical limits on number of usable cores, currently SetThreadAffinityMask only allows explicit scheduling of threads on 32 cores (the mask is a dword) on Win32. So that's our effective limit on number of cores. But as soon as there is a way to explicitly schedule them, we can handle 256 cores."

Out there it says that SP2 can handle scheduling of threads on 32 cores. But, I don't see that happening for more than 2 cores at all.
I am not sure, if I need to manually edit the 'SetThreadAffinityMask' value to improve the multi-core performance.

[Mickey_Techy]

Just finished reading the second link (and other links available from there) too.

If I am permitted to be a bit candid, I would like to admit that this much of information is a bit of overload for my 3 surviving brain cells

I would so appreciate if someone could translate all this 'techno' into plain English for people like me

[crim3]

Just try to add this to your fsx.cfg

Code: [Select]

[JOBSCHEDULER]
AffinityMask=14That should make FSX use the cores 2, 3 and 4. Most discussions about this says that it's better to left core 1 for windows.

[SpazSinbad]

crim3, thanks. I have wasted half an hour looking for 'fsx.cfg' in two OSs (Win7 32 & 64 bit) without success. Online have found "FSX CFG File Editor & Finder sxcfged.zip"at: http://flyawaysimulation.com/downloads-file-2794-details.html I'm hoping this will help.  

OOPS! did not realise that money has to change hands for the above utility. Not wanting to pay anything I have found this advice on the net that actually HELPS! :-)  Remember this is Windows 7.

C:\Users\'user name'\AppData\Roaming\Microsoft\FSX

[Mickey_Techy]

Crim3,

Thx for the information mate.

Could you point me in the right direction, where I could read more on setting the 'affinity mask' thing.
Have you tried this fix, and if yes, did it make a difference to your game play?

[Tregarth]

I have been thinking about going to an i7 processor so have been making some enquiries. At one time I was told by Alpine Computers (who build flight sim PC's) that FSX could not handle anything above a dual core processor so I bought a PC with an Intel E8400 Dual Core 3GHz processor.

Later I saw that Alpine were advertising PC's with i7 processors so I asked why they are now building quad core machines.  I was told that on starting FSX the OS (Win 7) looks at it, recognises that it really runs best in dual core mode and so configures the quad core processor so it runs as 2 x dual core processors which means more processing power, better frame rates or more detail etc.

This is what I am told by a machine builder so I tend to believe it.  I hope this helps.

Regards,

Tregarth

[Mickey_Techy]

Thx Tregarth.

Does that mean, the SP2 didn't actually make FSX multi-core capable as has been so claimed.

As a matter of fact, that is exactly what I have noticed too. With FSX running only One and a Half Cores are actually used, with all other cores lying unused.

[virtuali]

FSX is multi-core capable, there are moments where I can see all my 16 cores active (I use a MacPro with 2 Quad Core Xeon so, it's 8 real cores, 16 virtual)

The issue is, it doesn't happens constantly, because the multi-core capability it's used mainly by the terrain generation system and, it will not improve fps, at all. It will simply allow for a smoother flight with less stuttering, and less blurries.

People scream "we want multi-core" but, the issue is, having parallel processing, doesn't automatically grants better performances for every task. There are things that benefit a lot from multicore, like rendering or video encoding, because it's easy to have them run in parallel, because operations do not usually depends by the result of other operations.

A flight sim program can only use multi-core to a certain extent, because a lot of things are inter-dependent from each other, and doesn't parallelize very well.

[Mickey_Techy]

Thx Virtuali,

Coming from you, I will take it as a gospel.

Thx again.

/r
Mickey

[Paddles]

Just couple of screenshots of my Q9400 2.66GHz with AffinityMask=14. 

[Sludge]

Virtuali...

What affinity mask would recommend to run at for someone with a dual-core, then a quad-core?  I know its not the holy grail of FSX, using multicore processors, but what mask works the best in FSX, in your opinion?

Thanks
Sludge

[Orion]

If I recall correctly, the number you should use with affinity mask is the number of physical cores your CPU has, in binary.  Or something like that, from what I recall of one of NickN's tweaking guides anyways.

[virtuali]

A good setting might be the number formed by the number of physical cores you have in binary format, minus 1, which is the 1st bit so, the 1st core will not be used by the terrain system, and will be used by other tasks in FS.

For example, with a quad core, a good value might be 14 because

1111 1111 = 15 = all cores used (a quad core has 8 cores because of hyperthreading)
1111 1110 = 14 = all cores used except the 1st one