Exactly! After a fresh re-install, the game automatically sets the reserved space to 16 GB! This is your rolling cache! (Vanilla-sim without any add-ons) As long as you don’t exceed 16GB (rolling cache) there should be no problem with escalating ‘Reserved space’!
The default in PC is 8GB which is just about enough for the whole of London photogrammetry. Not that it matters much as PG loads and departs in considerably smaller blocks than that. The only time you might need more than 8GB is with ultrawide or multimonitor because of the wider FOV. Naturally RAM speed plays a big part, a minimum 3200MHz is recommended and I suggest no slower than CL18. Xbox uses Direct Storage to shared ram/Vram, you really cannot compare.
Just want to add my voice to the “Rolling Cache=Stutters” club.
I built a new PC (13700K, 4080, 990PRO) and didn’t realize rolling cache was enabled. Got inexplicable stutters mostly in photogrammetry areas. Stumbled by accident on the cache setting, disabled it, deleted the file and all the issues are completely gone.
This has got to be inefficient I/O handling on the cache file because you can read/write random data to a Samsung 990 PRO faster than my 500Mbps Internet connection can read, that’s for sure.
Yes that’s right. I think stutters start to happen when the rolling cache file is full and MSFS start to remove the old content and store the new one.
For sure, There’s some major cache logic and mechanism issues with MSFS rolling cache, which the dev isn’t aware of.
Just enlarge the rolling cache file with some gb and built on with itbecause it contains data from previous visited places also and you will have to rebuild it all if you delete it.
Also dont mix dx11 with dx12 but give each its own cache file in different directory.
But expanding make stutters go this i can confirm
I did that already. I set the size to 128GB. (with photogrammetry ON)
When it is still in filling-up stage (no rolling data), everything will be fine.
When it reaches the capacity and starts to roll the data, the stutter will always happen.
By doing what you said, it will only prolong the time until the bad stutters happens.
The larger the file size, the worse the stutters when it reaches the full capacity.
This i have noticed to but what can you do in the middle of a flight.
Sometimes i turn rolling cache off this can be in middle of flight but i do not delete
Glad I found this thread - I’ve also been having inexplicable stutters.
Deleted the rolling cache and they’re gone!
In two minds whether to leave it off permanently, or switch it on and wait for it to fill up again (and for the stutters to inevitably start).
Have my RC on an 8GB ram drive … never even a murmer of a stutter
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That’s a good idea!
The point about the rolling cache is that it “stores” data ready for use again without having to redownload it from the servers. Rolling means once it’s full it will replace old data with new.
If you tend to fly around the same area most of the time it is useful however if, like me, you tend to be always going somewhere new, not so.
If you have good internet speeds rolling cache should not be needed so turn it off. I would guess however it was introduced to look after those whose data streaming wasn’t as good.
As regards stuttering when full perhaps the processor is having problems finding and presenting what you’re asking for so a huge rolling cache is probably counter-productive.
I believe 8GB is a recommended minimum and 16GB suggested optimum. Personally it doesn’t seem to make any difference to my way of simming.
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The rolling cache is also useful when e.g. looking around the airport so unless it causes a specific problem I see little sense in disabling it. There are a few reasons it might not work so well.
If it’s on the same drive as the packages it may be competing for memory bandwidth
Slow HDD to be avoided as are any overfilled or unoptimised drives.
Slow ram, not just ram speed but latency also matters
Not enough virtual memory is also a suspect, I personally have a fixed 16GB on my C: drive with all other page files disabled.
Those with enough spare ram could set up an 8GB ramdisk rolling cache but of course this is then 8GB that is no longer available to other programs.
How does one know when the rolling cache is filled? I think there are two potential performance issues: Windows and MSFS. Because it is a Windows file, Windows manages all the file reads and writes. Windows keeps track of where the file is on the disk and protects the file from corruption. MSFS has to keep track of what info is being put into the cache and has to know how to retrieve that info. In other words, it is essentially a small database for MSFS. MSFS has to maintain this database purging info no longer needed. There is only one way to improve rolling cache performance and that is by changing the cache size. A bigger cache is not necessarily better. The best performing cache is when MSFS is not writing very much info but reading a large amount of data. The worst performance is when there is a large amount of data being stored but very little data being read. Each user has their own “profile” of their MSFS activity. The cache size should be determined by user’s activity and hardware. I’ve tried reducing my cache size in half giving a small performance improvement on some of my flights. I am trying different cache sizes to find the performance “sweet spot”.
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Agree and I think it wise to think in 4GB blocks. Taking cue from the manual cache a PG city the size of Madrid is about 8GB so there’s really no need to have huge rolling caches. I know some bespoke airports can be big but they are never that big.
And despite it’s name it’s not quite as simple as in one end out of the other.
I second the point about the cache getting full. My experience matches others’. I flew Heatblur Tomcat from Edward to Nelis today, low altitude flying all the way. I’m flying in VR, 70% TAA, GTX4090, c. 60FPS. About half way through the flight I started to get terrible shutters. I flew like that for a couple of minutes, constant shutters (cache at 16GB). I could see ground textures popping in below me… I paused the game, rebuilt the cache on a different drive - 40GB, unpassed, a smooth flight all the way to Vegas (alright Vegas at mach 1.3 is still a bit too much even for 4090, but you get the picture). I’ll report back if I get the same issue in a couple of weeks.
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Well add me to the people experiencing this issue. I stumbled across this thread last night after seeing it. (thank you to contributors).
I’ve been having so many issues with stuttering/pauses in sim over PG areas that I actually ended up turning PG off. Thought it was a SU14 thing, but now I see it’s a rolling cache file filling up and not being auto managed/cleared properly thing/bug.
I manually deleted my rolling cache (recommended 8GB) and recreated it blank and then went for trip over Paris with PG on and it was fine with no stutters/pauses. Previously it was a slideshow.
I’m surprised more people aren’t seeing this issue as we get more and more PG areas added in sim.
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Hi there fellow simmers
I am aware that this is a bug reporting hub, but i would like to read your thoughts on this topic.
I share mine here,
As I have adapted my view on rolling cache file and the cause of stutters, this because i think there is more in play on this rolling cache file.
What i am sure of is, rolling cache overtime gets corrupted.
My view is we setup up our sim and overtime we change settings
I mean if in time we make change to olod, tlod, screenresolution or even add on and sim update whether they are mandatory, wu, su, cu or auu and even gpu driver update and setting, can be debit to corruption of the file and these i mentioned are factored on timed when execute in the sim.
In fact i think that rollin cache will get messed up with all this data and imo will produce or at least contribute to stuttering and while we can alter/expanding roling cache we also create double data in this file which could conflict previous data if not cleared.
Rolling cache can be beneficial to heavy type of scenery like city and airports
But what exactly get saved in rolling cache files this i do not know yet for the above in this post mentioned, are there animated scenes involving moving traffic or animal animations or is it just static scenery and textures involved.
Regards
Sebastiaan
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I think you are right. It’s probably a good idea to clear it after every update including 3rd party scenery additions/upgrades, PG improvements, CU’s, WU’s and SU’s. I’m going to be more diligent in the future. I used to just ignore it for the most part. Which evidently leads to FPS/stutters & perf issues.
Just had another smooth PG flight over Paris again so clearing rolling cache is the way to go. I don’t have fast enough broadband to leave it permanently off.
In the past with the London scenery what i did was before did a flight to the city of London,
I flew a tour on the city starting high to low altitude almost touching the water these flights
Where stutery in the beginning but i didnt mind for i was filling the cache file.
This was in my point of view beneficial because after this i could almost fly almost stutter free and with highest olod and tlod setting in slower flying aircraft i still prefer the default C172 sp enjoying so many hours. But then you start exploring different city like Rome or Paris etc while cache build up
Then go to other continents and yeah changing a lot of settings .
Then on one day decide to fly London again and then you find stutters while flying over the city
This made me think my previous post.
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Had another example of this tonight. Been flying a lot in Europe. Switched to US southwest out of KTUS. Slight sign of stutters on ground, but ok to taxi. On the roll down the runway very stuttery. I pause sim during takeoff and go to settings, delete rolling cache and recreate it and head back into flight and it’s all smooth again. There definitely seems to be a performance issue with rolling cache when it fills up.