Just tested the normal a320 on 120hz and the sim runs to the second so it must be something to do with hi end aircraft addons.
A320 (v2) moving from 120 to 60hz on display improves cockpit clock time lag from 70% to 90% accuracy for me on Xbox. Interestingly, the chrono in the cockpit is spot on for both hz.
Pmdg clock stopped at the correct time when playing in a friends lobby today
Just want to chime in and say Iâm experiencing this issue as well. It might have happened in the past as I have noticed the clock go out of sync before but it didnât really cause any issues so I didnât pay it much mind. Iâm really noticing it with the 777-300. The really annoying part is that it seems like fuel flow is running at a real time rate so Iâm almost running out of gas on my flights. I havenât tested this with other aircraft but Iâve timed it a few times and sim minutes are taking anywhere between 1:15 and 1:20 in real time.
I cleared and turned off rolling cache, uninstalled two airports and 3 or 4 planes that Iâd purchased and it did not help.
Iâve been doing some more investigating using the pmdg aircraft and what Iâve noticed flying with a friend. If I sit inside cockpit and use the map you can watch his plane literally walk away from yours
But viewing the aircraft outside they seem to match speed so the issue with sim rate lies inside the cockpit somewhere.
This needs sorting as itâs destroying the Emerson
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You using the 777 or the 737? I did a flight with the 737 the other day and didnât experience any noticeable time lag. Happens in every 777 flight though.
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Itâs the tablet. Specifically the map view. Iâve been flying in the 777 today and havenât had any time lag and the only difference is that I didnât put either tablet on the map.
I did quite a lot of testing of this on my XBX a while back. Itâs hard to reproduce, seemingly a combination of time compression and use of the EFB map in the PMDG 737-600 would cause it to happen on occasion. When it did occur, the clock could clearly be seen to be running at almost half speed, switching the map view off restored normal time instantly. I did report it to PMDG and to be fair they said it had been seen a number of times but reproducing regularly was almost impossible.
Where did you get the information that the XBox does have a HW clock from?
If that would be the case there shouldnât be any problem with the time lagging in the game as all displayed clocks, including framerates could be derived from that clock.
My assumption is that the XBox Series X has no HW clock.
Modern CPUs always include very accurate hardware clocks, but that doesnât stop the software from inventing its own software clock if it chooses, as seems to be the case here.
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If you turn on the Xbox it will display the time of day on the home screen. This isnât possible without a hardware clock keeping track of time when the machine is off.
This doesnât follow. Rather it appears to be only counting time that passes during frame rendering, and not time âbetweenâ frames, or something similar; thus itâs failing to account for some of the passing time.
Remember also that the sim has the ability to speed up or slow down time â itâs not trying to match 100% all the time, only when it is set to 100%. But itâs sometimes failing especially on some xbox systems.
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As soon as the XBox is started a WLAN connection is started so the time could be derived from the network. Valid question would be whatâs the deal when the box is not connected⊠
One more thing: a hardware clock usually needs a battery and I cannot see any access on the XBoxes to change it if emptyâŠ
On the other hand it seems that the lag is dependent on the load and definitely is variable.
What I also experienced is that during a group flight with a group of PC simmers even though having the exact same settings, plane, throttle etc I couldnât keep up and my plane started to fall behind.
Who started this bizarre rumor that Xboxes have no way to keep track of time anyway? Iâve spent more posts debunking it than anything. 
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So tell us: if the XBox has a HW clock how can I change the battery?
afaik modern computers use a rechargeable battery. Thatâs why if you leave a machine unpowered long enough itâll lose the clock data and reset to some past date, but once youâve had it powered it recharges the battery and it keeps time across power-downs again.
You know what, Iâll ask around and see if anybodyâs done repair work on actual machines and can tell us more from having seen the motherboards and worked with them.
In any case battery backup is unrelated to the ability to keep time, and IIRC from earlier in the thread keeping it on real time still reports the real time, so it knows what time it is. Itâs failing to keep track of passing time as being part of the simulation, while itâs running.
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Evening everyone.
Iâve just turned off all my hud info and the clock is now only 1 second behind per minute Hopefully this helps others
Do you have the same issue if you follow the OPâs steps to reproduce it?
Provide extra information to complete the original description of the issue:
Are you using DX11 or DX12?
Are you using DLSS?
If relevant, provide additional screenshots/video:
It seems that sim rate is slowing for no reason.If you want real time sim rate you need to set normal 1x sim rate.To do that you need to spam PgDn (for me that key slows sim rate ) so that sim slows till the end.Then you need to hit PgUp exact 4 times (key for Sim rate + for me) for real time sim rate
I have a problem with sim rate. It`s slowing for no reason. I need to reset and set to 1x every few minutes
Is it with any aircraft or with a particular aircraft?
Looks like a different issue of whatâs being described in here but you might want to check e if you do not have any keybinds assigned by mistake to decrease sim rate.
I assume you are on Xbox. Do you have a 120 Hz TV? If you run with 120 Hz on your Xbox the sim will slow down a lot. I had that issue and switched back to 60 Hz and now I only loose like 2-3 minutes after a 10 hour flight ~
More details here: For Xbox Series X players with 120hz TV
Yes I find it runs best at 4k 60hz instead of 120hz.