Jump to content
The simFlight Network Forums

FSUIPC stutters in FS9

Recommended Posts


I have found FSUIPC will cause stutters across FS9 and FSX and almost certainly P3D although I could not test in this sim.

Anyone can try this in any of these sims by looking at the areas of their sim that causes most stutters. Note the stutters that you have and then try the same situation without FSUIPC installed.

I tested mostly in FS9 on Win 10 and Win 7. I understand FS9 is no longer supported but I feel the issue is likely carried through all FSUIPC versions. A fix for one version would likely be a fix for all versions and easy to implement to all sims once the core problem was found.

I found you can install a default FS9 and it will run completely smooth. If you install FSUIPC and nothing else, you will now have stutters in your sim. Registered or non registered FSUIPC versions both behave the same.

I also found from a quick test FSUIPC appears to function fine on a Win XP install. This XP test wasn't comprehensive but indications certainly appeared to be as such. I'm thinking the issue may possibly be related to flight sims/FSUIPC running under 64bit versions of Windows?

There have been other threads in the past on this and I recently also received confirmations from other users of my findings.

The topic below is a typical example of a past thread:

I hope this can be looked at and hopefully addressed. FSUIPC is a critical component and something almost all FS users need to run.


Link to comment
Share on other sites

6 hours ago, Skywatcher said:

I hope this can be looked at and hopefully addressed. FSUIPC is a critical component and something almost all FS users need to run.

I'm afraid FSUIPC3 is no longer supported. And when unregistered it really does nothing. Even the data is presents in its offsets is nearly all obtained directly from sections of FS9 memory, just as with FS98, FS2000, CFS and FS2002 and the first versions of FSUIPC.

With FSUIPC4 and FSX, judging from your report it looks like any stutters which appear to be due to FSUIPC will be down to SimConnect, because an unregistered FSUIPC (one of your tests) does absolutely nothing after initialisation except receive the data it requested from SimConnect during its initialisation. Perhaps you need to consiider re-installing FSX, or at least starting it without the FSX.CFG file so that it reverts to defaults.

The only known cause of stutters in FSUIPC is the use of the AutoSave, because it is then asking SimConnect to save a flight at set intervals. But even then they aren't noticeable unless you are using advanced add-on aircraft which also save data, or, less likely, your disk system is slow or fragmented and there's not enough cache space in memory, or disk caching is turned off.

You should check the FSUIPC log file to see if any errors are reported. Maybe if the Sim is running "unleashed" (i.e. no frame rate limit or Vsync set) there's not enough time for even the actions of filling the offsets to be carried out. Timeouts would result in re-initialisations which would certainly cause a stutter.  The lg would show this. With FSUIPC4 there's a parameter you can increase which sets the time out for SimConnect data updates. It's normally 1 (1 second). You could increase that. (This wouldn't apply to FSUIPC3).

Otherwise, I'm sorry but, because there's nothing to look for as a cause of stutters within FSUIPC I cannot even start "looking at" it.

Incidentally, FSUIPC3 dates to 2003 whilst FSUIPC4 to 2005.  Perhaps it's time for a move to a more modern system?



Link to comment
Share on other sites

I also can confirm exactly the same thing on a brand new install of FS9. Stutters WITH FSUIPC and zero without. This isn't on 'obsolete' hardware or operating system. W10, SSD drive - which doesn't run any sim any better then W7 or XP did by the way.  

As no doubt the micro stutters on FSX and P3D (no longer have as I moved forward on to FS9) and possibly even MSFS mostly likely emanates  from FSUIPC even after the save flight is switched off. 

After the test many others on forums now reporting the same thing. 

Link to comment
Share on other sites

This topic is now closed to further replies.
  • Create New...

Important Information

By using this site, you agree to our Terms of Use. Guidelines Privacy Policy We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.