FSX SP1:New tweaks

In fsx.cfg


There is a tweak to control scheduling of threads on cores.

It is not recommended to change these settings unless you have a performance reduction and/or maxed out CPU loads in the PerfMonitor. The tweak is

Edit:Fixed a typo here
n num of cores scheduled
1 = 1 core 0001
3 = 2 cores 0011
7 = 3 cores 0111
15= 4 cores 1111


There is additional code to reduce blurries. If you get random texture tiles that appear in a solid color this may help.

In some cases, the textures generated from this code can get throttled and will be timed out. The time out config value is



The default is 30 frames.


There are new config items to control VSYNC for fullscreen and windowed separately


ForceFullScreenVSync, default is TRUE

ForceVSync, default is FALSE

We have seen cases where when VSYNC is on in fullscreen causing major fluctuations in frame rate especially when setting the rate limiter above 45. If you run into widely fluctuating FPS in fullscreen when aiming for above 45, try turning VSYNC off or reducing below 40.


For the dusk/dawn textures some people feel, subjectively, the result is too dark or too light. There are 2 items that allow the transition time to be changed:




acceptible values are 0 to 65535.


DAY: 32768

NIGHT: 4096

These represent the amount of 'ambient' light at the ends of the day/night blend threshold. Zero is perfect dark, 65535 is full day sun at noon in the summer.


There is a tweak that helps with panel updates, especially the glass panel. If you use the glass panel and notice very slow updates. There is a 2 part tweak:



By default this UINT32_MAX (i.e. four billion or so) so it has no effect.

Setting it to zero effectively forces full texture updates instead.

Setting it to smaller numbers (1-1000) might improve performance if the card is slow at full texture updates and does not have a high overhead for incremental updates.



By default this is 0 (i.e. disabled) so it has no effect.

Setting it to 1 (enabled) causes us to merge all of the dirty rects into a single large dirty rect. This means that we will only do a single partial texture update.

This may work well if the card is slow at full texture updates and does have high overhead for incremental updates.


There is a scenery tweak to eliminate very small objects, which can reduce render time.



Basically this culls out small model parts (e.g. air conditioners on roofs of buildings, aircraft doors) if their radius would occupy less than the specified number of screen pixels.

The default is 1.0 (i.e. 1 pixel). 2, and 4 are the next 2 settings we advise. Can significantly improve performance but may cause “popping” of small objects