Hi,

I've seen a decrease in performance as well. Lightning is not networked, hope that gets done in the future... Bolts going off all over the place could trigger a seizure.  

24 minutes ago, GoranM said:

Most likely culprit is a rogue plug in that may not be compatible with 12.3.  

You should always have a test version of a beta and stable release as your main sim.  

Possibly a scenery issue. Updating my main install to 12.3 got me down to 25fps, all cpu time.

Clean install with all the same plugins is getting 90fps at higher settings at the the same start location and weather.

Something isn't quite right, but its definately of non default origin.

Edited September 5, 2025Sep 5 by mSparks

I run a basic vanilla system - mixed results. Start and Load time had improved, a few menu changes here and there noted such as time setting, performance after that was erratic. Small no dense scenery location with default Laminar aircraft about a 25% increase in FPS indicated and light and screen responses seemed more balanced or less erratic (No bloom) next to a high demand model in a high demand traffic environment (scenery weather and model) FPS crashed back to less than 25 FPS and at time was 4 up and down all over. I am getting strange artifacts such as light poles now casting a bizarre shadow across the model that is not a shadow but well just weird. Left it alone at that point - still have an issue that has been bugging me for some time the failure of the sim to shut down and exit cleanly or in a timely fashion without resorting to task manager to kill the processes, if anything it is worse now!

So far except for removing one ai plane that was using another planes sound, no issues, that probably due to fmod update. No noticeable change in FPS. Find it funny people giving fps changes in %. Was is 5 to 10 fps or 50 to 100 fps, they are both doubled framerates

I run a simple test - a default simple model the C172 (coldndark) at a country aerodrome, no AI no other addons, real time weather and no time manipulation, FPS went from 40 to 50 consistently. Next a complicated addon the FELS 747-200 at a major aerodrome with addon scenery (YSSY) i used to get about 30 FPS cold n dark this dropped to 24 and stayed there, changing views from inside to outside dropped the FPS to 4 at worse it then went up and down depending on how I manipulated the view or moved the viewpoint, never got above 24 and there was not weather it is a CAVOK day at the moment. View changes from out to in gave me the dreaded dark cockpit syndrome which took several minutes to readjust itself. OK but the whole program hangs on using the exit and shutdown menu command. That is just the detail of my experience. 

I suspect that it is not a Laminar XP issue at all but MS and the operating system attempting to do something uselessly helpful (the industry standard these days add junk and hide it) and no I don't want AI with that or MS pretending that they will fix the problem just going to report it as they hang the system further! The solution is not MS but LINUX in my view after my experience of spending days removing the metastising ADOBE software from my system without the continous struggle between MS and Alphabet trying to run my world - vented enough for today!

Edited September 5, 2025Sep 5 by coastaldriver

I'm eager to try it more - just pushed the update...

Looking fwd for when Austin finally get's his modified (some good months ago) flight dynamics to fix that rolling bug with prop aircraft... Will it be for 12.4?

9 hours ago, GoranM said:

Most likely culprit is a rogue plug in that may not be compatible with 12.3.  

You should always have a test version of a beta and stable release as your main sim.  

No plug ins here, even deleted the contents of the plugins folder just in case and had the installer put back anything needed.

And not complaining as it is VERY smooth - smoothest sim I've operated in almost 30 years - when I run with the Lossless Scaling which is how I always run XP12.

So very happy with this update, just sort of curious what's happening under the hood to drive the CPU time so high (and maybe that's somehow leading to smoothness, who knows?)

When my actual FPS fell before 20 before I'd get a warning etc. certainly not a silky experience.

Will play with it more this weekend.

Well there IS a new cpu core management system in this one. So some change wouldn't be totally crazy to consider in a beta release but it should be small. Running the FPS function is the only way to know with certainty. There's also now a FPS-test path-recording function in the Dev menu which I had never paid much attention to in the past. Can now make our own more easily.

now this is whats im interested in,

 

 

Airbus A330-300

This update introduces extensive enhancements across the Airbus A330-300’s avionics, flight planning, and flight control systems. Key improvements focus on VNAV fidelity, autopilot behavior, realism, and pilot usability. We now also support a fully functional Secondary Flight Plan (SEC F-PLN).

Flight Management and Navigation

Support of a secondary flight plan (SEC F-PLN).

CRZ FL ABOVE MAX FL is now a clearable message.

Added FPL preview for CO ROUTEs; STATUS page now shows pilot-defined points, navaids, and routes.

SIDs beginning with an IF (Initial Fix) without a connecting leg from the departure runway are now handled as per real-world logic — no NAV arm, HDG PRESEL used.

Step climbs now possible via FCU (dial and push ALT).

Improved climb/cruise/descent predictions with winds aloft, step climb fuel use, and constraint handling.

Explicit discontinuities inserted after segments requiring manual sequencing.

Enhanced VNAV logic: early descent, path capture from above, smooth acceleration, better path prediction in varying conditions, support for arbitrary deceleration segments.

Autopilot & Flight Control Enhancements

Accurate roll rate and alpha protection response under FBW.

Corrected autopilot disengagement during rollout with pedal/tiller input.

More realistic auto-trim reset and deceleration logic post-touchdown.

Supports managed climb/descent during missed approach and into subsequent approach.

Airbus-style level-off preview now on the ND (replaces “banana”).

Improved FMA consistency during approach, go-around, and transitions.

Systems, Displays & Quality-of-Life Improvements

V-speeds suggestions now available, based on minimum available V2 — just double-tap the LSKs after entering the desired flap setting in the FMS.

Fuel prediction logic reworked for consistency across flight phases.

Realistic baro/STD handling per pilot side, including the correct warnings in case of no mismatches.

New ECAM messages and ATSU simulation: ATIS, METAR, and PDC now fully supported with memo display, controller cab selection, and delay simulation.

Improved climb thrust and climb fuel burn.

More accurate cruise fuel burn.

Improved autoland handling.

FQ and totalizer sync corrected, no more negative fuel prediction bugs.

Improved autobrake deceleration behavior and make deceleration less aggressive, close to real deceleration values.

Visuals

For those with cpu time issues.

 XPD-17269

Check your X-Plane.prf and look for

_snd_use_ip_51 = 1

If it's that bug, setting it to 0 probably brings CPU times back to normal,

Worked for me. 

2 hours ago, fluffyflops said:

now this is whats im interested in,

 

 

Airbus A330-300

This update introduces extensive enhancements across the Airbus A330-300’s avionics, flight planning, and flight control systems. Key improvements focus on VNAV fidelity, autopilot behavior, realism, and pilot usability. We now also support a fully functional Secondary Flight Plan (SEC F-PLN).

Flight Management and Navigation

Support of a secondary flight plan (SEC F-PLN).

CRZ FL ABOVE MAX FL is now a clearable message.

Added FPL preview for CO ROUTEs; STATUS page now shows pilot-defined points, navaids, and routes.

SIDs beginning with an IF (Initial Fix) without a connecting leg from the departure runway are now handled as per real-world logic — no NAV arm, HDG PRESEL used.

Step climbs now possible via FCU (dial and push ALT).

Improved climb/cruise/descent predictions with winds aloft, step climb fuel use, and constraint handling.

Explicit discontinuities inserted after segments requiring manual sequencing.

Enhanced VNAV logic: early descent, path capture from above, smooth acceleration, better path prediction in varying conditions, support for arbitrary deceleration segments.

Autopilot & Flight Control Enhancements

Accurate roll rate and alpha protection response under FBW.

Corrected autopilot disengagement during rollout with pedal/tiller input.

More realistic auto-trim reset and deceleration logic post-touchdown.

Supports managed climb/descent during missed approach and into subsequent approach.

Airbus-style level-off preview now on the ND (replaces “banana”).

Improved FMA consistency during approach, go-around, and transitions.

Systems, Displays & Quality-of-Life Improvements

V-speeds suggestions now available, based on minimum available V2 — just double-tap the LSKs after entering the desired flap setting in the FMS.

Fuel prediction logic reworked for consistency across flight phases.

Realistic baro/STD handling per pilot side, including the correct warnings in case of no mismatches.

New ECAM messages and ATSU simulation: ATIS, METAR, and PDC now fully supported with memo display, controller cab selection, and delay simulation.

Improved climb thrust and climb fuel burn.

More accurate cruise fuel burn.

Improved autoland handling.

FQ and totalizer sync corrected, no more negative fuel prediction bugs.

Improved autobrake deceleration behavior and make deceleration less aggressive, close to real deceleration values.

Visuals

But .. but !  is this already in the present update ????

 

Do I really need to describe what I think about it?

 

Hammers my Ryzen 5600x, mostly during loading... Then as I use RTSS to limit FPS to 30, it lowers while on session.

Using the Ryzen App that monitors CPU, Cores, Temps, I see a much more even distribution of load among my 6 cores (SMT is set to Off) than when running MSFS 2024).

I guess the big difference between MSFS 2024 and Xp12 lies on the streaming approach / WASM... MSFS relies a lot more on the network than Xp12, for the good and for the bad...

GPU ( 3060 Ti) also now getting higher temps.

This release of Xp12.3 runs very very smooth! No stutters, at mid/high settings. Nothing at Ultra.

Like the lighting, the colours, the weather! Lighting and colours, airport and all lighting systems look much more true to real in Xp12, that's for sure...

Weather effects, like flying in the vicinity or across hazardous weather surely has consequences !

Have to give that A333 a new try ...

Edited September 5, 2025Sep 5 by jcomm

10 hours ago, Republic DC9 said:

No plug ins here, even deleted the contents of the plugins folder just in case and had the installer put back anything needed.

And not complaining as it is VERY smooth - smoothest sim I've operated in almost 30 years - when I run with the Lossless Scaling which is how I always run XP12.

So very happy with this update, just sort of curious what's happening under the hood to drive the CPU time so high (and maybe that's somehow leading to smoothness, who knows?)

When my actual FPS fell before 20 before I'd get a warning etc. certainly not a silky experience.

Will play with it more this weekend.

Not just plugins, scenery addons can go a long way to performance hits. Remove all addons.

If anybody gets autopilot disconnects in the A330, file a bug describing the circumstances under which they occurred.