After having read numerous posts that this parameter does either nothing, or nothing useful with FSX SP2/Accel and a quad CPU, I have nevertheless tried to set it to 0.18, as was recommended somewhere on one of forums..

 

FIBER_FRAME_TIME_FRACTION=0.18 // default=0.33

 

To my surprise, my experience is that it has improved smoothness and performance in heavy scenery, like Vancouver+.

 

So, I wonder, is this just a placebo effect, or do other users have a positive experience with this setting??

 

My system config in my sig..

Mine is set to 0.1

 

Definitely makes a difference. There are many placebo tweaks out there but this isn't one of them. It goes hand in hand with several things though so have a good read.

It's true, Lower has better performance but at the expense of blurrier textures. I have FSX set at .33 (default) but seems to vary by computer hardware performance. I have Prepar3D is .40. Its explained in the P3D tuning guide.

Yeah, it's a great tweak!

 

Mine is set at 0.15,which I find is a good compromise brtweem performance and texture clarity.

Hi Bert, I see no difference whatsoever with this tweak. I have tried mine at 0.18, and other value and settled with default .33. I do get more blurries with lower values.

 

There are many more important tweaks that give me smoother performance or better fps.

According to NickN from Flight1 over at Simforums, FFTF does nothing and is not needed for multi core processors beyond FSX service pack 1.

 

(source - http://www.simforums...479.html#170479)

 

FIBER FRAME TIME FRACTION - With ANY multicore processor AFTER SP1 USELESS WITH TEXTURES However this can be used with systems that run TILE PROXY

........

 

 

Are you running a single core or multicore processor?

I find very few people running FSX on single core slugs today

FFTF was something that was addressed in the ORIGINAL release of FSX

 

After SP1/SP2 Aces FIXED the problem and FFTF is no longer needed as a matter of fact its not doing anything with multicore processors after SP1

 

FIBER_FRAME_TIME_FRACTION determines the maximum amount of time per frame that we will run fiber jobs on the primary thread. We measure how long it took to simulate and render and then multiply that time by FIBER_FRAME_TIME_FRACTION to determine how long to run the fibers. For example, if it took 10 milliseconds to simulate and render and FIBER_FRAME_TIME_FRACTION was set to the default value of 0.33, then we would allow the fibers on the primary thread to run for up to 10 * 0.33 = 3.3 milliseconds. For fraction values of 1.0 and 2.0, the time given to fibers would be 10 milliseconds and 20 milliseconds, respectively.

The operation of FIBER_FRAME_TIME_FRACTION on single core machines has not changed since RTM.

 

On multi-core machines in SP1, we moved many fiber jobs off of the primary thread and onto secondary threads. Since FIBER_FRAME_TIME_FRACTION only affects scheduling of jobs on the primary thread, it will have less of an impact on the performance of Flight Sim on multi-core machines. In fact, we moved so many jobs off of the primary thread that there probably isn’t enough fiber work left to soak up the full time allowed by the default value of 0.33.

 

Therefore, on multi-core machines, there’s very little reason to tweak the fraction because it really only impacts performance of single core machines.

 

 

and

Please emphasize the pointlessness of tweaking this value on multi-core machines.

 

Further, setting it to values greater than the default value on single-core machines can increase frame rate volatility because it increases the amount of time we *might* allocate to fibers if there is adequate work waiting in the queue. When the queue is full, we’ll allocate the full amount of time to fibers but when the queue is empty, fibers get no time because there is no work to do. If the rate of new jobs entering the fiber queue is bursty and the full time allowed for fibers is large, then you can imagine how this would increase volatility.

 

If people feel like the fibers aren’t getting adequate resources, they would be better off leaving the fiber fraction alone and just lowering the frame rate limit slider, which helps divert more CPU time to primary thread fibers without increasing volatility.

 

More info on it - http://blogs.msdn.co...f-the-week.aspx

 

 

Just an fyi, I reinstalled FSX completely 3 days ago, and I do not have the FFTM line in my FSX.cfg anywhere.

This was after installing FSX and then installing Acceleration (which automatically includes both SP1/SP2).

 

On my previous FSX installation, I had skipped Acceleration and did both SP1 and SP2 separately and I STILL didn't have the FFTF line in my FSX.cfg.

As far as I can tell, this is a line that has to be manually added, and I'm guessing that SP2 or Acceleration both delete it from the FSX.cfg as it's not needed post SP1.

Here are Nick's recommended settings.

He does specify an FFTF value of 0.12.

 

http://www.simforums.com/forums/different-scenarios-different-settings-thats-how_topic41798_page3.html

Just an fyi, I reinstalled FSX completely 3 days ago, and I do not have the FFTM line in my FSX.cfg anywhere.

 

The fact that something isn't in the cfg doesn't mean much. Some thngs are only added to the cfg so you can actually change them. Take TERRAIN_MAX_AUTOGEN_BUILDINGS_PER_CELL. This isn't in the cfg by default, but it IS used by FSX and there IS a default! Only if you want to CHANGE the default, you will have to add the line to the cfg manually. MS didn't find it necessary that this setting would be changed so it's not in the cfg but it can be added if you want to. And that goes for a lot of other settings.

 

(Why MS chose to add other settings to the cfg that usually aren't changed also, I don't know.)

Hi Bert, I see no difference whatsoever with this tweak. I have tried mine at 0.18, and other value and settled with default .33. I do get more blurries with lower values.

 

There are many more important tweaks that give me smoother performance or better fps.

 

If you see no difference then that's great. Your hardware is working well together without having to shunt tasks from the CPU to GPU etc... so you should be happy that 0.33 works well :) For some of us, it's a great tweak because smoothness is more important than the occasional blurry ground texture. I'd certainly also leave mine at the default if I could but the lower value certainly improves the experience for me when using complex aircraft.

 

I do use a higher value when flying basic, low & slow aircraft though, when the blurry textures are more prevalent anyway. You just don't notice them so much in fast and high machinery so the compromise works well.

In my guide, there is slightly updated section on FFTF tweak. It explains what it does.

Btw mine is at 0.15 for now. Doing some tests between FSX and P3D.

Interesting feedback! So I'm not alone in this...

 

The combination of:

 

FSX on an SSD, Nvidia Inspector set to 1/2 framerate Vsynch, and FFTF=0.18

 

has provided me with an almost effortless feel in the air - even when low over KSEA, which used to be

a real problem area, ever since I got the first copy of FSX installed.

 

And all that without touching the CPU, or motherboard... I'm pretty happy!

According to NickN from Flight1 over at Simforums, FFTF does nothing and is not needed for multi core processors beyond FSX service pack 1.

 

Hes changed his stance on this lately....

He's changed his stance on a lot of things, Glenn.... new hardware and upgraded OS's do that!

 

I'll also bet it's the case with the new DX10 mods that Steve Parsons is working on. We know all of the tweaks and tune-ups for the DX9 version of FSX, but it doesn't necessarily mean they all work in DX10, and likewise - there are settings for DX10 - some we don't even know about yet - that won't work for DX9.

Hes changed his stance on this lately....

 

I saw the new link posted.

Does anyone know if he has an updated guide with new changes like FFTM?

Hi Bert,

As I ran into this issue again reading this forum I like to give you my experience.

 

Mine is set to 0.1 and I like to thank Word Not Allowed very much for his guide, which I followed TO THE LETTER. The only thing I could not manage was this Desktop Windows Manager part of the tweak.

 

I abandoned FSX and completely switched over to P3D; I have I think the most ordinary configuration / setup in the world: I5-760 @ 2.80 GHz (slightly overclocked to 3.3 GHz) NVIDEA 450 GTS, I use RexE (weather engine disabled and substituted by "Live Weather Engine" of Opus Software).

 

All this give me the following results:

 

EDMA - Augsburg 29-30 FPS (Standard P3D airport)

EDDT - Berlin-Tegel 28-29 ,, ( same )

EGLL - Heathrow 29-30 ,, ( same )

------------------------

EGLL - Heathrow 24-25 ,, (UK2000 Extreme)

LEBL - El Prat Barcelona 23-24 ,, (Mega Airport Aerosoft)

LEMD - Barajas Madrid 24-25 ,, ( same )

EDDF - Frankfurt 22-23 ,, ( same )

EHAM - Schiphol Amsterdam 16-18 ,, ( same )

 

Everybody knows, that Amsterdam is the biggest FPS eater.

 

So again, THANKS a lot Word Not Allowed!

 

salu2

Fdovillamil