CTD at 3.1GB

[viking]

Some key posts on this and related threads (experts feel free to note any errors or insights):

• Post #11
• Post #27
• Post #40 (this is where the 500/430 ratio seems to have originated.)
• Post #66
• Post#278
• Post #313
• Post #1 (adjacent thread: Caution about memory optimisers)
• Post #64 (adjacent thread: Caution about memory optimisers)
• Post #68 (adjacent thread: Caution about memory optimisers)
• Post #70 (adjacent thread: Caution about memory optimisers)

Wiki article (draft)

 

Thanks,

STEP

 

OP follows

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First of all I wanted to thank you all for the great work you have done with STEP. Skyrim is the first game I installed on this computer and you guys have made it an AMAZING game. That being said, I have an issue that I hope you can help me solve.

 

My setup:

Vanilla Skyrim

gtx670 w/ 4GB @1080p w/ latest driver

16GB Memory

3770K at about 4GHz

Windows 8 64bit

ENB 149

Ultra settings

Highest available texture/quality

Mod Organizer

Step 2.2.1 + Skyrim Revisited + others

 

I have noticed a post here and there saying that Skyrim can't really address more than about 3.1GB of memory without issues. This seems to jive with my experience, meaning I CTD every time my memory hits that mark, but I couldn't really find anything definitive on the topic. The issue with googling the topic is the pre 1.3 skyrim that couldn't address more than 2gb of memory.

 

My mod list is mostly based on STEP which is why I came here for help, with about ten mods added onto the end (Interesting NPCs, Detailed Cities, Economics, COT, and a couple others). The reason I haven't included my mod list is that it doesn't seem to matter. As long as I keep the memory usage below 3GB I can have pretty much any combination of mods.

 

What I have tried so far (in no particular order):

• resetting ini files
• removing enb
• not using attklt
• only using a new game
• removing all mods and adding one by one until issue crops up
• running as admin
• watching the papyrus log - it seems relatively clean, no obvious errors right before CTD

Yes, I can run STEP just fine without any issues, but I also never get near 3GB of memory. I have tracked VRAM usage as well and have seen a max of 2.7GB/4GB.

 

As an example of where I might run into issues: I start a new character with Alternate Start. I start with Breezehome. Run out of Whiterun, past the Brewry, up the hill to the bandits. Enter the cave (watching memory usage with Elys MemInfo), and it dies right after I see 3GB. I have this same issue not using AS, sitting through the intro, and then running over to whiterun.

 

I'm sorry if this post is all over the place. I have spent more than a week trying to solve this issue, and the only solution I have found is to reduce memory usage. I have got to the point where I can exchange two texture packs and get into the cave without a CTD, but with both I get a CTD. I didn't even think texture packs should even affect CTDs, but I'm relatively new to Skyrim on the PC, so I could be wrong. I also found I could get a bit further with ENB turned off, but would still crash once I got above 3GB of memory. Finally, if I reload a game after a CTD, I can play just fine...until I reach 3GB of memory.

 

I really hope you guys can help. I more than willing to try anything at this point, besides just disabling all of the mods.

[z929669]

Hmm, I defer to the hardware experts that lurk these forums; however, it is plausible that the issue is not really memory usage at all. This could be a side effect of the problem. More likely, it is a setup issue. Are you checking memory usage of TESV.exe using Process Explorer?

[Neovalen]

3.1GB has been the limit I have hit as well. I think it's due to Skyrim being a 32bit program and not 64bit but thats just idle speculation with no proof.

[MontyMM]

Have you tweaked your ugridstoload settings? My VRAM usage doesn't usually go that high unless I'm experimenting with higher ugrids.

[SSL]

RCRN has initweak to allow skyrim use more RAM on their www. Try that and tell us whether it helps. BTW their shadows tweak also looks promising.

[MontyMM]

I'm not at all convinced about that tweak.  I tried it, and then looked into it.  Here is the definition of that setting:

 

iMaxAllocatedMemoryBytes

This is the maximum amount of memory the VM will allocate in total for stack frames. If an allocation would push memory usage over this limit, the VM will instead wait for more memory to be freed. Increasing this value may improve performance in high-stress situations with lots of scripts running, but will use more memory. Note that it is possible to exceed this value temporarily while loading a save game due to slightly different allocation ordering.

Max: 2147483647 (2GB)

Default: 76800 (75kB)

 

What RCRN is recommending doesn't tally with an understanding of this definition.

[Gyro]

I've read that Skyrim simply can't handle itself over 3+ gigs of RAM. It sucks for those of us with systems that can handle much more, but it seems there's no remedy for it at the moment beyond making sure you DDSopt everything.

[viking]

z929669 - I have not ProcessExplorer to track TESV, I will definitely try this tonight. I typically have Resource Monitor or Task Manager running in the background and I try to catch the memory usage that way. ProcessExplorer should be much more reliable. As I mentioned, though, I watch the memory usage live using MemInfo in skyrim. The numbers I see there jive with what I see in Task Manager/Resource Monitor. 

 

Neovalen - It is nice to know that other people have had similar experiences. How have you dealt with this issue? 

 

MontyMM - I actually have not tweaked my ugrids setting specifically because of the negative effects I have heard that it causes. BTW, I believe my Ram, not my VRAM, is the issue, though I never did ask the question of whether or not there is a maximum amount of VRAM that skyrim can address. My gut tells me this is not the case based on my limited GPU programming experience.

 

SSL/MontyMM - I have tried tweaking iMaxAllocatedMemoryBytes with no real effect.

 

I am thoroughly surprised that this is not an issue that others have run into before. STEP has some great guides dealing with reducing VRAM and increasing CPU, but I haven't seen anything relating to memory usage besides a handful of ini tweaks. Is this really an uncommon problem?

[viking]

Gyro - I've heard the same thing, but most of them seemed to be individual experiences and I did see a few posts to the contrary which is what lead me to make this post. What makes you suggest DDSopting the textures? I can see how that would directly affect VRAM usage, but I was under the impression that textures aren't loaded into memory first.

[SSL]

Apparently it does (at least parts of them) - IIRC someone mentioned that at Skyrim Revisited thread.

[MontyMM]

MontyMM - I actually have not tweaked my ugrids setting specifically because of the negative effects I have heard that it causes. BTW, I believe my Ram, not my VRAM, is the issue, though I never did ask the question of whether or not there is a maximum amount of VRAM that skyrim can address. My gut tells me this is not the case based on my limited GPU programming experience.

 

I'm not suggesting that VRAM is the issue - I was taking the high usage as a possible indication of increased ugrids, which would have been a likely suspect.  I don't think that VRAM is likely to be a problem here.

 

Unfortunately, DX9 based games will use main memory to mirror some textures, which can cause problems.  Interesting article here.  It is also suggested that games that were written with the 2GB cap in mind often have bugs that affect the addressing of higher memory space.

 

Sadly, I think we're hitting the limitations of a creaky engine here.  I'm afraid that only a major update from Bethsoft can solve these problems (they originally promised a DX11 version of the game, but I'm not holding my breath.)

 

Of course, we cannot be certain that memory is the culprit in your case.

[viking]

MontyMM - That is an excellent article the certainly supports what you're saying. Unfortunately for us, there are so many unknowns that I don't think we will be able to satisfactorily get to the bottom of the issue. That update (that was for Vista...so presumably it carried forward) seemed to say that it moved video ram mirroring into a different address space, removing the issue for the most part. However, it says that for directx 9 and earlier, the issue isn't fully resolved. My understanding is that Skyrim is based mostly on directx9, with some pieces of 10.

 

What I don't understand is if the issue isn't completely solved, and some of VRAM is mirrored in RAM, wouldn't this show up in Task Manager's memory usage for TESV? I would think that it would appear as if the entire address space were in use, no matter if it were mirroring or if it were holding other game elements.

[viking]

SSL - I do remember coming across something like that in the Skyrim Revisited thread. I'm looking through it to see if I can find it again.

[JudgmentJay]

I can say with complete certainty that the Skyrim engine chokes at around 3-3.2GB physical RAM usage. Also, while the amount of VRAM that Skyrim can use is limitless, textures ARE loaded into physical RAM as well, so using a ton of high resolution textures will only bring you closer to instability.

[viking]

JudgmentJay - I assume you are basing this on personal experience? Any idea what kind of ratio of VRAM is loaded into RAM? It obviously isn't 1 to 1 (otherwise it couldn't use unlimited VRAM). I might run a test tonight to remove all of my textures from MO and see how Ram and VRAM change. I'll post results.

[JudgmentJay]

JudgmentJay - I assume you are basing this on personal experience? Any idea what kind of ratio of VRAM is loaded into RAM? It obviously isn't 1 to 1 (otherwise it couldn't use unlimited VRAM). I might run a test tonight to remove all of my textures from MO and see how Ram and VRAM change. I'll post results.

Yes, it's based on extensive personal experience. I'm not sure the exact ratio... I don't check VRAM usage much, but I always have physical RAM usage displayed on the screen when I'm messing around with mods. When I go from a vanilla install to a vanilla install + Texture Pack Combiner, it's +~600mb of physical RAM usage when loading into Riverwood.