Stutters and CPU spikes in regular intervals

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Hello friends, I am struggling with big problem. I have new computer, there are spec:

- Motherboard: ASUS P9X79-E WS

- Proc: Intel(R) Core(TM) i7-4930K CPU @ 3.40Ghz (6 cores) 

- Graphic: 3 x NVIDIA GeForce GTX Titan X (now no in SLI mode)

- RAM:  2x Samsung M378B5773DH0-CH9 2GB (this is only because I have my Corsair 4x8GB sent on guarantee - but I have read that FSX don't need more - and I see this because when it is on, Memory is on about 70%)

PCU: Corsair HX1200i

Monitors: Samsung 4K UE40JU64 (but I have it in 1920x1080 resolution) 60Hz

- Acer 1920x1080 60Hz

System: Windows 8.1 64bit



Yep, so I have installed FSX:SE firstly on my SSD (where is my system) but due to problems, which I will describe you in moment, I uninstalled it and installed again on my HDD. But problem still occurs. (yep, I defragmented the HDD disc).

I have no addons (but I tried with PMDG and it is no different). So my problem is that I have a lot of sttuters in game, it doesn't matter where, which aircraft, what time. Flight is very smooth and everything is so good,( I can get 300 FPS on one monitor), but these stutters are so annoying. It is for about maybe one second (sometimes it is no stutter but something like slowing down simulator). There is NO FPS drop (or maybe counter can't catch this drop, because these stutters are very fast).

I've tried everything, tweaking FSX, changing NVIDIA settings, fully uninstalling fsx, hyperthreading on and off, overclocking cpu and default clocks and nothing helps. I found out that the fps limiter in fsx sometimes causes more stuttering (I don't know why) so I downloaded RiviaTuner to lock FPS. Problem still is there.

Finally I downloaded Process Explorer. And there I saw something interesting! The picture with description is below, but in generally: I have some stutters (purple arrows - maybe some of these smaller bars were stutters too, but I couldn't see them); and the biggest mystery VERY BIG USAGE OF CPU in regular intervals. I think if we knew why it is, we would be closer to eliminate stutters. But really weird thing is that stutters appear on the  begining of this "jump", after everything is okay... until another stutter. 😞

I think you can help me, because I am struggeling with this for 5 days! I spent about 30 hours of reading topics, testing and everything.

Please help me with this:(

Thank you in advance!


This is photo of CPU usage from Process Explorer:

Intervals between green high bars are about 1 min.

k9vxar.pngPS. I added this topic in this forum because it is stricte connected with fsx and no (I hope) with hardware issue.

Edited by gaddemyt
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you might want to check out this website. Also, are you using nVidia Inspector? What are your settings there?

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Knowing what your nvidia settings and FSX scenery settings look like would help.  But...

Your processor running at 3.40 GHz is ok, but the closer you get to 4 GHz the smoother FSX becomes, so overclocking might help if you have a good CPU cooler.

It sounds like your computer has 2x2 GB or RAM.  Yes, FSX will address only 4 GB, but with only 4 GB in your computer and Windows 8.1 - 64 bit operating system, I suspect that Windows is using 1GB, if not a little more.  That does not leave FSX much room.  You would be better off with at least 8 GB so that FSX can use its maximum of 4 GB and Windows, video driver, audio driver, etc. can use as much as they need without interfering with FSX's use of RAM.

Another thing that can cause stutters are background processes.  Automatic updates and virus scanners can cause stutters and pauses at regular intervals.

Finally, there is an excellent guide to setting up your computer and FSX here at Avsim.  I highly recommend following the guide.

Edited by stans
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I found out that these CPU spikes are due to lighting texture refresh in FSX which is every 61 seconds. I don't know how to fight with it.

This is what I've done: Set AffinityMask to 56 (which means I am using only 3 last cores) - and this reduced these spikes by half (only because I am using half cores now :D) but stuttering still occurs.

I have tried different settings in nVidia Inspector and this helped a little but still I have too much stutters for this specs.

I can try starting everything from 0, but I need your help.

@speedyTC  My settings: (as I said I was trying everything and this is why I can have little mess here - I can try to start over!)



@stans I overclocked it to 4125, but came back to original because I thought there can be the problem. I have good temps of CPU and GPU. 

I know more ram would be better but as I mentioned before - I was watching Memory usage and this is in 70% all (system + fsx). I will upgrade it when I receive my Corsairs, but for now I don't think the problem is here.

I turned off (and even uninstalled) my antivirus and turned off any updating from windows. I was watching also processes in background and every was under 1% usage of CPU.

I was reading almost every guide about tweaks and settings (bible from NickN, here on Avsim, Word Not Allowed guide and more). Still have stutters. I think we should try everything step by step, but I don;t know so much about performance settings, so that is why I am writing here. Maybe we can do this step by step.

Thank you for replyes though. And hope to have this problem solved quick.

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So here is another perspective.

4GB of ram isn't enough to operate a modern computer, much less throw in trying to run a game. Forget almost everything from the past about tweaks and drives. Absolutely install FSX on the SSD and as much as you can that is associated with it. You probably won't need ANY tweaks to your system or the cfg file. Start with default FSX, including in game default settings, though you can set these high fairly soon. Turn off background services, though if your computer is running properly these don't effect FSX like they used to. Update all drivers.

Lighting texture refresh? I'm skeptical. 300 fps is a waste of computing power. Why would you need more than 30 or 40 max.

Just some things to think about.  

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Hi Bob. I will install it on my SSD for sure. I didn't said I am flying with 300 FPS, I only told you I can get so much. I am trying to limit FPS by FSX's limiter but it seems to not working properly for me (when I am using limiter in FSX I have more stutters), so I was trying with RiviaTuner limiter and that is okay. 

Yes, I agree with you, I need more RAM, but I am waiting for it. 

Regarding to Lighting texture refresh - this is information from other forum, where someone had similar problem to mine (I mean these CPU spikes). This is really odd these spikes appear every 61 seconds (exactly!). Maybe this is something else? I don't know. But I know it is from FSX.exe (Process Explorer and Task Manager showed that).

Anyway, I have to wait for my RAM, I don't know how long, but I will definitely write if I had any informations.

For now I will try any other things, which I think can cause these stutters.

Thank you for reply. If someone else has any idea - I am waiting for suggestions.


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