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uGridsToLoad Limit: maximum allocated RAM on 64bit < 3GB?

Question

Preface:

 

Hello there, i've got a tricky question (i think) about HW + modding, probably aimed only to people with high-end rigs (8GB or more of RAM + 3GB or more VRAM [non-splitted] + SDD + Windows 7 64bit) that have tried to push Skyrim to the limit.. (for reference i've got a i7-2600K 16GB DDR3 + GTX580 3GB slightly OC + windows n game installed on 128GB SDD).

 

I'm using UGRIDS=9 and about 60+ mods (mostly texture mods from STEP), including a combination of Skyrim HD, Realistic Overhaul and Serious HD, all of them at the maximum quality available. Still running on Skyrim 1.4.27 since NVidia Ambient Occlusion for me is a must and apparently is still not solved.

 

 

Short version:

 

As i understand since v1.3 Skyrim should be able to use up to 4GB of RAM memory (the maximum for a 32bit application on a 64bit OS).. has anyone actually managed to have it working with anything above 3GB?? for instance TESV.exe using something like 3.5GB according to windows task manager? if so did you do anything special to archive that??

 

 

Long version:

 

As we all know there are lots of myths and theories regarding the value ugrids and that can lead to "instability", same thing about using lots of high-res texture mods.. Well i've got the theory that the only real problem when increasing this value or the size of the textures is either lack of VRAM or lack of RAM.. I've got a very stable game using UGRIDS=9 and only recently i found a few specific outside locations where the game would CTD after walking from another outside location (would not CTD if i load a savegame already on the location)..

 

I'm pretty sure VRAM is not a problem (using always less than 2GB - 65%). Total amount of memory is obviously not a problem either (16GB).. However checking my main memory usage i realized CTDs always happens when the game tries to use more than 3GB of RAM. I think that happens when "usable" RAM is already almost filled and when you move to a new area with lots of new resources that have to be loaded there's just no space to put them.

 

I have spend quite some time googling and checking both HW and Skyrim forums with no luck.. have tried using Game Booster 3, changing boot options from the command line "bcdedit /set increaseuserva 4096", changing Skyrim.ini iMaxAllocatedMemoryBytes=4294967295 (4GB) and still the same problem.

 

So is it really an issue of software-limited maximum allocated RAM per process? If so is there a way to use more than 3GB? Or am I totally wrong and it's just a problem of the GPU/CPU not being able to cope with so much information?

 

 

I'm a bit annoyed because i have the feeling that if i could really use the whole 4GB as advertised then all my CTD's would be gone and I could even possibly run with all textures mods + UGRIDS=11.

 

I know there are other ways i could go about this like optimizing the textures, reducing settings to use less memory, etc but that's not the point of the question for now..

 

 

Any ideas?? Thanks in advance!

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You can do it yourself: go to the "Support/troubleshooting" section-> find your thread -> don't open it but click and hold the title to edit.

 

If you are the OP you can also go to the OP, Click Edit > Full and change the subject and even the thread tag.

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@MadWizard

 

Yes i guess i'm quite lucky as ugrids=7 with almost all STEP texture mods (at max quality) is rock-solid for me. But you know, you always want more than what you have :-) As i found out, even after you remove the VRAM problem you still face other ones, which haven't been able to fix so far..

 

Anyway here's something i didn't mention before that might help you stabilizing ugrids=7 and that you could test quite easily, another theory of mine :-P

 

Probably you've heard about the rule where exterior_cell_buffer value must be (ugrids+1)².. Well that didn't make much sense to me.. i believe ugridstoload is the number of cells that fit in one side of a "square" around you, so if for instance ugridstoload is 7 that means you are loading a matrix of 49 cells in total (the cell where you are + 48 cells around you).

 

So in my tests with ugrids=9 i tried the equation ugrids²+1 and found that i had less CTD's than with the other one (i'm using 82 = 9²+1). Haven't tested it with ugrids=7 but you could try.. instead of the usual 64 check exterior_cell_buffer = 50 (7² + 1), it will use much less memory and should be enough to buffer all your cells.

 

Also make sure you use the value i mentioned bSelectivePurgeUnusedOnFastTravel=1 on SkyrimPrefs.ini, that helped me stabilize ugrids=9 a lot. Finally when testing don't load savegames saved with different ugrids values (even though in theory you can load savegames with lesser values than your ini). Skyrim doesn't like that much.

 

 

@Admins

 

do you think it could be possible to change the name of the thread and replace the word skyrim with ugrids or ugridstoload? (thought about changing it after creating it to make the subject clearer, but couldn't find out how). Thanx!

 

 

 

Thanks for the tip, will give the lower exterior cell buffer a shot. I dont fast travel at all, so would the selctivepurge function still work?

 

Im thinking that with these tweaks, and using the new beta DDSOpt i might be able to achieve ugrids 7! Time for some testing!

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@MadWizard

 

I think selctivepurge works as well when you load a different savegame, as i noticed being able to load more times without getting a CTD.. but as always it's only empirical evidence :-)

Let us know if the tips work for you!

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So far not much improvement. Still crash happy at 7.

 

I use the newest pre-release DDSopt on every texture i could get my hand on. It dropped vram use by about 15%, so im now well clear of my max vram use of 2GB. Peak is at 1.75 so far. Still crashing.

 

uExterior Buffer does not seem to make a difference if its and 50, 64, or 100.

 

I cant tell if selectivepurge works yet.

 

Another user on the bethesda forum also reckons that crashes occur not just because of close to peak vram use, but also occurs due to far more scripting, ai mechanics, and pathing that occurs at 7 and higher. Therefore, it might be worthwhile tweaking papyrus settings as well as multithreading to help here. So i will be messing with those next.

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RE multithreading... be careful with this one, as it is counterintuitive because of the way Skyrim allocates resources. MontyMM provided some good detail in these forums somewhere on this, and s4n/Fri had some good weigh in.

 

I'd check out those posts first. lots of good info there.

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Good advice z92, however, for completeness sake i will need to retest in any case due to the intervening patches. With all the optimization they have been doing with patches, who knows if these values still behave the same way?

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So far not much improvement. Still crash happy at 7.

 

I use the newest pre-release DDSopt on every texture i could get my hand on. It dropped vram use by about 15%, so im now well clear of my max vram use of 2GB. Peak is at 1.75 so far. Still crashing.

 

uExterior Buffer does not seem to make a difference if its and 50, 64, or 100.

 

I cant tell if selectivepurge works yet.

 

Another user on the bethesda forum also reckons that crashes occur not just because of close to peak vram use, but also occurs due to far more scripting, ai mechanics, and pathing that occurs at 7 and higher. Therefore, it might be worthwhile tweaking papyrus settings as well as multithreading to help here. So i will be messing with those next.

did anyone ever have good results using multithreading and papyrus tweaks in the ini? i've been testing for 2 months and i can run skyrim at ugrids=9 fine (from 1 end of the map to the other for hours. vanilla w/ Official hires packs). i can even add the full Texture Pack Combiner. but if i add in Monster Mod or anything that adds spawns (Automatic Variants, Skytest), then i get crashes ONLY in the area south of Windhelm. the steamy hotsprings tundra area, and up the path a ways toward Fort Amol. if i add a few spawn mods like MM + AV+ ST then i get crashes elsewhere.

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I'm getting the same issues, check out my post here for all the technical info.  I'm using STEP 2.2.2 on a clean build. 4K textures.  When it hits ~3 boom CTD

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Using more than uGrids=5 on a heavily-modded Skyrim is just asking for CTDs, especially if you use very high resolution textures. There has to be a trade-off somewhere.

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Hi.

It was said earlier in this post that the vram would affect the stability of ugridstoload 7-13.

I have the Geforce Titan with its 6gb the max settings i can go with is 7 but its unstable.

 

Tried 9 but that results in the game being stuck during loading a saved game.

 

Im running with a manually merged texture meshes pack, collected from all the mods included in the tex pack combiner + a few others.

 

I messured max vram to 5.2 GB at 5760x1080 resolution

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Hi.

It was said earlier in this post that the vram would affect the stability of ugridstoload 7-13.

I have the Geforce Titan with its 6gb the max settings i can go with is 7 but its unstable.

 

Tried 9 but that results in the game being stuck during loading a saved game.

 

Im running with a manually merged texture meshes pack, collected from all the mods included in the tex pack combiner + a few others.

 

I messured max vram to 5.2 GB at 5760x1080 resolution

VRAM has nothing to do with it. It's physical RAM that's the issue.

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6GB VRAM is not likely to be any use for Skyrim.  It seems that the textures in VRAM must be copied into RAM.  Skyrim cannot use more than 4GB RAM, and seems to become unstable even at 3GB. 

 

I have experimented with ugrids quite a bit, though it is not recommended.  My experience suggests that the two key factors in ugrids stability are RAM usage and shadows.  I can run stable with ugrids at 9, so long as I reduce my mod load to keep RAM usage comfortably below 3GB, reduce shadow settings, and avoid mods that are likely to increase the number of shadows processed. 

 

The question of shadows is just my theory from my own testing, and should be considered anecdotal, but the memory concerns are widely reported.

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