Preload radius - what exactly does it do?

[sirrah]

I play DCS for quite some time now, but I've always wondered what preload radius (in the graphics settings menu) does exactly.

 

Well, I take a wild guess, but I've tried different preload values and never noticed any difference (not ingame nor loading times). Can anyone explain to me how it works?

[BIGNEWY]

Preload radius is the amount of terrain you are allowing to preload.

[sirrah]

Does this preload only occur during the loading screen? Or will it constantly be active during flight? (will it influence framerate or just loading times?)

[Gnadentod]

It does preload a circle (or square, ask ED developers) around your starting position while loading into the RAM/VRAM. It also does load a new circle (/square) once you come too close to the edge of your initial preload radius while you're flying. This is the reason why a SSD is far superior to HDD in terms of performance not just in pre-flight loading but also while flying.

[Drac]

Is it best to max out preload to reduce access to the drives? What is the recommendation for this setting?

[twistking]

Is it best to max out preload to reduce access to the drives? What is the recommendation for this setting?

if you run on a HDD you'll notice the effect of the setting balancing initial loading time against the chance of small lags or short stutter sometimes during flight.

on a ssd i did not see those little lags at all, even if i set pr relatively low. i therefore advise to NOT maximize pr, since it will not give you benefits, while increasing memory foodprint and theoretically increasing initial load times.

also there still seems to be a risk of performance degredation with excessive vram usage due to some memory management issue.

( https://forums.eagle.ru/showpost.php?p=4033533&postcount=28 )

even if this does not apply to your system, you will probably not gain anything from super high pr, if you are running from a sdd.

[sirrah]

if you run on a HDD you'll notice the effect of the setting balancing initial loading time against the chance of small lags or short stutter sometimes during flight.

on a ssd i did not see those little lags at all, even if i set pr relatively low. i therefore advise to NOT maximize pr, since it will not give you benefits, while increasing memory foodprint and theoretically increasing initial load times.

also there still seems to be a risk of performance degredation with excessive vram usage due to some memory management issue.

( https://forums.eagle.ru/showpost.php?p=4033533&postcount=28 )

even if this does not apply to your system, you will probably not gain anything from super high pr, if you are running from a sdd.

I see. Thanks for explaining :thumbup:

[Drac]

if you run on a HDD you'll notice the effect of the setting balancing initial loading time against the chance of small lags or short stutter sometimes during flight.

on a ssd i did not see those little lags at all, even if i set pr relatively low. i therefore advise to NOT maximize pr, since it will not give you benefits, while increasing memory foodprint and theoretically increasing initial load times.

also there still seems to be a risk of performance degredation with excessive vram usage due to some memory management issue.

( https://forums.eagle.ru/showpost.php?p=4033533&postcount=28 )

even if this does not apply to your system, you will probably not gain anything from super high pr, if you are running from a sdd.

 

Roger...will reduce my preload setting.

[fitness88]

I found running with preload maxed out actually smoothed out performance. Perhaps 8gig v-ram and 64gig ram allows for less file swapping back and forth?

[Worrazen]

The whole thing around texture streaming, loading, is too complicated for users to figure out exactly. I'm kinda interested to fiddle with this, but ultimately the solution is to just get more RAM, and with the recent advances in memory, hopefully we'll finally see the rise in capacities that are long overdue.

 

However for PCs it's a bit complicated due to split system RAM and graphics VRAM, system RAM can only work as a cache while the key thing that do have enouhg VRAM to fit everything that you would videw in a normal mission, without causing any trashing, the DCS engine needs to have good system between RAM and VRAM so that VRAM doesn't hit limit, which means it's okay if some things are streamed in later, and this does happen as I've seen, but it should not stop engine execution like I've seen DCS do, it sutters when it's reading off the disk, this may be even a clue if there's a code issue or a thread issue that when reading from IO is busy it stops execution, that is for sure a bug except if the content that has to be loaded is important, but the map tech needs to be done for streaming in mind so the parts of the map are split in loadable chunks and not into too big of an area that the engine needs fully loaded to be able to run it. that's the rough idea, but I would need to dig into it again to see if it changed or not in recent months.

 

It's more worthwhile if we post suggestions on how it should be working, not that we know best ofcourse, but DCS has huge potential and core DCS improvements would go a long way, but I totally understand the module development at this time, people are stoked for F-16 it seems, let them have it I say.

Edited October 13, 2019 by Worrazen

[twistking]

I found running with preload maxed out actually smoothed out performance. Perhaps 8gig v-ram and 64gig ram allows for less file swapping back and forth?

 

interesting. are you sure, this was not a placebo effect?

 

when i was still running from a HDD, the effect was pretty obvious, but it wasn't a problem of smoothness, but just those 1seconds of lag/stutter after a certain amount of flying. i'd take off, fly a little bit - get the little lag while my HDD read-led would flash - then smooth flying again for another 20min, then a small lag again etc. ...

 

however it's also important to know that the different maps utilize different data streaming. NTTR handles data streaming different than caucassus f.e.

it could very well be, that preload radius has different effects on different maps. oh boy...

[Davee]

I found running with preload maxed out actually smoothed out performance. Perhaps 8gig v-ram and 64gig ram allows for less file swapping back and forth?

 

+1

 

32Gb of RAM and SSD