a very short argument for the rolling cache

[Ixoye 1,812]

It is the opposite for me, rolling cache will introduce stuttering, I have had it off since game release without pauses and stuttering problems, I have 250mbps fiber and 1tb m2ssd.

Edited April 19, 2021 by Ixoye

[RaptyrOne 1,398]

3 minutes ago, Ixoye said:

 

It is the opposite for me, rolling cache will introduce stuttering, I have had it off since game release

 

Yes, and this makes sense because your PC is not just flying the sim, it is now having to process data for writing to disk. CPU is working harder, RAM too no doubt. Those CPU cycles have got to come from somewhere. Stutters. Probably placing greater demand on the incoming data line too, as it is likely downloading more that the circle around your aircraft.

 

[Gridley 257]

Great discussion.  The only thing I'll add is that, if you choose to enable the cache, it's best to delete the rolling cache prior to updating the sim, and then create a brand new rolling cache after the update.  Many issues with old data messing with the updates leading to artefacts.

[Silicus 849]

15 minutes ago, Gridley said:

Great discussion.  The only thing I'll add is that, if you choose to enable the cache, it's best to delete the rolling cache prior to updating the sim, and then create a brand new rolling cache after the update.  Many issues with old data messing with the updates leading to artefacts.

This for sure. Having to update the rolling cache every four weeks or so due to an update is NOT user friendly, especially for the  'internet speed challenged'.

[vgbaron 3,486]

My experience was a little different. On my system with a 2080ti I had cache off and had no problems at all. Upgraded that system to a 3090 and turned up my settings. I noticed that after about an hour of flight my fps started to tank pretty badly to the point of becoming a slide show.  Set the cache to 48G on an ssd - have not had a fps drop since. I'm thinking the increase in LOD from 100 to 200 is the culprit making me need the cache. All other settings are on ultra.

[cavaricooper 2,613]

So are you happy with 48G Vic?

Did you try smaller and larger? How did you finally arrive at 48G? More than all that, where on earth did you find a 3090? I’ve been looking since November and can’t find one at retail pricing...

Ta- C

[reignman40 450]

1 hour ago, vgbaron said:

My experience was a little different. On my system with a 2080ti I had cache off and had no problems at all. Upgraded that system to a 3090 and turned up my settings. I noticed that after about an hour of flight my fps started to tank pretty badly to the point of becoming a slide show.  Set the cache to 48G on an ssd - have not had a fps drop since. I'm thinking the increase in LOD from 100 to 200 is the culprit making me need the cache. All other settings are on ultra.

Interesting, maybe the rolling cache is more beneficial to those with higher scenery/terrain settings. It would make sense. 🤔

[sightseer 895]

I would bet having an AMD Ryzen would be helpful.  I think it has dedicated lanes to communicate more efficiently with an M.2 drive.  Maybe those with current gen Intel processors have more stutters using the cache than those with Ryzen systems.

and then theres the issue where different PG areas seem harder to download for some reason.  For example:  I'm currently rebuilding my cache which means redownloading Florida currently.  I started with a flight from the addon KPCM (Plant City) to the addon KCLW (Clearwater) and I had fairly severe pauses especially when turning south to land at KCLW.  The next day I started at Kissimmee (not sure of the code) and flew to Orlando executive and had no major pauses at all.  I then decided to fly from Orlando Executive to the area on the south side of Tampa and as I approached (about where KPCM is), I started getting pauses again.  It continued with pauses until I was close enough to the coast that much of the Tampa area had filled in.  I then turned north to land at KCLW and had none of the major pauses I had had the day before.  

Today I start off at a little airport on a little island south of Miami and head north to land at KFLL following the outer chain of islands and I experienced no major pauses at all.  I had very minor pauses along the way and a couple of slightly larger pauses as I got closer to Ft Lauderdale but then it was uneventful as I circled and landed at KFLL.  Some PG areas just seem easier to download than others.

If anyone who doesnt use the cache would like to do a test flight -- fly Orlando Executive towards downtown Tampa and then land anywhere you want.  See if you get pauses as you approach Tampa.  I think there may be something wrong in that area.

 

[sightseer 895]

On 4/19/2021 at 10:24 AM, cavaricooper said:

Have we settled on an optimal size for the rolling cache?

I don't know what the optimal size for a cache is but having one thats 100Gigs doesnt seem to hurt too much but I do think that the upper limit size would be dictated by how fast your processor can get information into and out of that cache.  A slower processor or one that doesnt communicate as efficiently may require a smaller cache but I dont know and Im not a computer expert by any means.  I tend to think that 100Gigs is the largest anyone should ever go though as I apparently downloaded a good section of Florida for less than 8 Gigs.

23 hours ago, Moria15 said:

how would this work if you have cached a default airport and then replaced it with a custom one or had a custom one and then updated the custom one?   I am just wondering how these requests determine the difference in the area from whats been seen before

Just a thought.. perhaps I will set up one and try it to see what happens.

Graham

I'm not sure this is how it works.  I think airports are just part of the Virtual File system and are never in the cache so if you update one, it just gets replaced like flight sims have always done. I could be wrong as always 🙂 

[marsman2020 1,310]

7 minutes ago, sightseer said:

A slower processor or one that doesnt communicate as efficiently may require a smaller cache but I dont know and Im not a computer expert by any means.  I tend to think that 100Gigs is the largest anyone should ever go though as I apparently downloaded a good section of Florida for less than 8 Gigs.

For any sane implementation there is a lookup table somewhere that keeps track of what is in the cache so the sim can quickly check against it to see if it needs to go out to the Internet or not.

The size of that lookup is much much smaller then the size of the cache itself.  It's just a list of what data items are cached.

Larger caches should work fine on any CPU.

The fastest commercially available internet connections are around 1Gb or 125 MB/s which is slower then a good SSD.  200-300mbit seems to be a common top end for what is widely available, which is 25-37MB/s.  Any cache located on an SSD should be faster then going out to get the data on the internet, assuming the implementation isn't totally wrong.

[MrFuzzy 2,117]

24 minutes ago, marsman2020 said:

The fastest commercially available internet connections are around 1Gb or 125 MB/s which is slower then a good SSD.  200-300mbit seems to be a common top end for what is widely available, which is 25-37MB/s.  Any cache located on an SSD should be faster then going out to get the data on the internet, assuming the implementation isn't totally wrong.

MSFS barely downloads at 10 MBit / s and for short periods. I did a lot of tests and the local storage of the textures is not really relevant.

[sidfadc 1,340]

23 hours ago, RaptyrOne said:

Yep, that’s my experience too. Rolling cache simply does not provide any benefit and as such, is a hinderance. What’s the point of writing GB’s of data to your SSD when it does nothing? Asobo have yet to demonstrate how it works, or that it even does work. It stays off on my  PC until proven otherwise.

 

Agreed you would think we could look at some documentation to understand how the word not allowed thing actually works and then make a decision whether to enable it or not.  Too many unanswered questions and lots of guessing games.

Edited April 20, 2021 by sidfadc

[cavaricooper 2,613]

It’s the only $100+ program I’ve ever bought that comes without a manual.... hopefully MS will rectify that one day.

[Isaiah53six 134]

This may have changed recently (with updates  but a few months back  when I was using 100gb rolling cache I would get a lot of stutters.  Went back to 8gb (default) and the sim seems to run much smoother.

Edited April 21, 2021 by Isaiah53six