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Oblivion And Physical Memory Usage

Know Your RAM Ceiling And How To Fix It

UPDATES: - Well, sorry for the bad news WinXp 32bit users... LAA carries no benefit for you. After testing, it turns out that there is a slight decrease (1.7gb) in the amount of RAM Oblivion.exe will allocate for it's process. This slight decrease was probably because I didn't restart Windows before the test with LAA enabled. So I would go as far as to say there was no change in memory usage at all. Without LAA enabled, Oblivion was able to reach 1.8gb . This test was performed on a fresh install of WinXp 32bit SP3 with only Vanilla Oblivion, SI, All DLC plugins, and the 1.2.0416 patch. XP was using 175mb of memory for the OS. 3.25gb was the reported installed memory.


- Although LAA allows system ram to be used as VRAM when it runs out, after thoroughly testing the limits of VRAM this week, I've decided that it's unstable for Oblivion. I consistently experienced CTDs when attempting to max out my VRAM. The most common of these CTDs were cell changes or running a PCB command. It is best to try to create your mod load order based around the dedicated VRAM on your graphics card. I believe some overage of VRAM should be fine, but I was trying for very large amounts. (200 - 500mb over dedicated)
Once I removed a few mods that lowered my VRAM usage back down to normal levels (600 - 900mb) all cell changing and PCB commands were stable and no CTDs occurred over many hours of game play. With that said, for now it is not recommended to push your VRAM very far beyond it's dedicated amount.

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* Here is a video of http://www.youtube.com/watch?v=jq5uJQKMV6s. This is an example of a CTD that will consistently occur (without LAA enabled) regardless if you have a ton of ram. This test was created with a 100% vanilla game (patched to 1.2.0416) with shivering isles and KoTN. - (credit to http://www.gamesas.com/bgsforums/index.php?showuser=572837 for this sweet HD vid!)

* Here is a video of http://www.youtube.com/watch?v=dgPsdraKyBQ
Although this test proved that system memory can be used for VRAM when the dedicated VRAM on a graphics card runs out, exceeding your dedicated graphics VRAM isn't recommended and will cause instability when changing cells and running PCB mods or commands.

* Please be aware that the patch listed on this page may produce undesirable
results if used on an altered or modified Oblivion.exe file.

* A important reminder to XP players using, or thinking of using the 4gb LAA patch within this page.

If you're on XP and benefiting from LAA then you probably don't REALLY want to try the game w/o OSR heap replacement. If Oblivion allocates more than 200 MB of small heap allocations on its native heap on Windows XP performance starts plummeting towards unplayably slow. And if you're not using more than 200 MB of small heap allocations, why would you need LAA? On other versions of Windows it's not a big deal though.

(For those who do not know what OSR is. It stands for http://www.gamesas.com/bgsforums/index.php?showtopic=1074487.)

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How to determine if your physical memory usage is the cause of your CTD issues.

* The type of CTD that this topic will identify a fix for is the type associated with players that have a large amount of resource intensive mods loaded at the same time. These types of mods include... High resolution texture replacements (QTP3, Bomret Normal Textures), Any mod that adds a multitude of new NPCs, (Modems City Life etc...) Large overhaul mods (FCOM, OOO, MMM etc...) Large landscape mods (Unique Landscapes, RAEVWD, Better Cities, Open Cities etc...) If you don't run these types of mods, your CTD issues are more than likely not going to be related to this topic. (note that I am in no way stating that the above mods contain issues. Only that they use large amounts of memory that Oblivion was not initially intended to run.)

I've noticed many topics are created with titles like "Oblivion Crashes After 20-30 Minutes"
A crash that seems to happen as if it has a timer is almost certainly going to be from the
Oblivion.exe process reaching it's allocated memory peak. Especially when Oblivion may be
loaded with a ton of mods that are filling up available memory very quickly.

If you run a modded Oblivion, and have a moderate to heavy mod load you will eventually hit
a memory ceiling resulting in a CTD. Even if you have 4gb, 8gb or even 16gb of ram, a memory
ceiling crash is imminent. The best that can be done is to prolong it using the patch below...

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How to monitor your memory usage while playing the game

If you're experiencing consistent CTD episodes such as the infamous "20-30 minute CTD"
Please follow these steps in order to monitor your games memory usage. You will know if
you have hit a ceiling once you notice your crashes happening around the same amount of
memory usage on the Oblivion.exe process. (it's best to test within the same area your
last crash was experienced. Or in a largely NPC populated city, i.e. Anvil docks is a good place to test.)

1. Run Oblivion in window mode either by changing the setting in the Oblivion Loader.exe
or by changing the Oblivion.ini value bFull Screen=1 to bFull Screen=0

2. Open task manager by pressing ctrl + alt + delete and choose Options.
Be sure to check off "Always On Top". Next, be sure you select the processes tab and also sort
by memory so that the program using the most memory is on top.

3. Make sure your desktop resolution matches your in game resolution.
This is to ensure that when you run Oblivion in window mode, you won't experience any major overscan on your monitor.

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The Fix

Oblivion was only meant to allocate up to 2gb of ram. This actually turns out to be around 1.6 - 1.75gb of ram on most systems.
Once your Oblivion.exe process reaches around 1.6 - 1.75gb of memory, you will experience a CTD.
However, with this http://www.ntcore.com/4gb_patch.php you will be able to raise the ceiling up to 3.8gb (these numbers vary depending on XP or Vista/7 32bit or 64bit)

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Helpful notes

1. Add the LAA http://www.ntcore.com/4gb_patch.php to your Oblivion.exe and not obseloader.exe (I made this mistake at first)
Also, be sure to make a backup of your original Oblivion.exe file. *Please be aware that the patch may
produce undesirable results if used on an altered or modified Oblivion.exe file.

* A important reminder to XP players using, or thinking of using the 4gb LAA patch within this page

If you're on XP and benefiting from LAA then you probably don't REALLY want to try the game w/o OSR heap replacement. If Oblivion allocates more than 200 MB of small heap allocations on its native heap on Windows XP performance starts plummeting towards unplayably slow. And if you're not using more than 200 MB of small heap allocations, why would you need LAA? On other versions of Windows it's not a big deal though.

2. Adding http://www.tesnexus.com/downloads/file.php?id=23208will provide system stability improvements as well as decrease CPU load and memory fill rate."Saw my CPU usage drop from 50% to 25% and the amount of time which my memory increased or filled up was cut by half. This is because of the 30fps cap set by the OSR default .ini file"

3. Adding a PCB mod will help increase system stability by purging cached memory. This includes both physical system memory and your graphics card video ram (vram) This basically frees up the cached memory that no longer needs to be stored. That is to say it will prolong the amount of time before your memory fills up to it's ceiling point. Search on http://www.tesnexus.com/ for a good purge cell buffer mod. Or just search the topics here.

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How I figured this out

I stumbled across a mod that I determined had a memory leak after noticing my Oblivion.exe process
memory size would continuously increase to a consistent size limit before crashing.

From this, I decided to create a test which would prove Oblivion had a memory ceiling that causes a consistent CTD when reached.

After installing Vanilla Oblivion with SI and all the DLC packages,
I loaded the mod with the memory leak and ran Oblivion in windowed mode so
that I could monitor the Oblivion.exe process with task manager.

In a nutshell, I purposely overloaded Oblivion's physical memory process in order to see where it's breaking point was.
This helped me simulate the type of CTD that most of us experience from a heavily modded game.

Just like we know what our video ram limit is for texture mods, wouldn't we want to know our physical ram limit for game stability?

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My To Do List

• Provide a comprehensive list of Oblivion.exe memory ceiling points w/ and w/out LAA, separated by OS (WinXP/Vista/7)
  
• Run a low VRAM to high system ram stability test which will focus focus on utilizing system ram used as VRAM while remaining under Oblivion.exe memory ceiling w/ and w/out LAA to understand how stable system memory is when used as VRAM.
  
• Determine which OS offers the most available total memory headroom for overall system stability.
  

far327, I have yet not had RAM usage exceeding about 1.1 GB in my game. So I'm unfit to participate. However, if it was found that indeed there is a "crash ceiling", it might be an argument in favor of using some type of cell buffers purging tool. I'm using one, for better or for worse, and it keeps my RAM usage civilized it seems.

Although I remember not long ago (10 days?) a guy mentioned in the OSR thread he once crashed whith RAM using in excess of 3 GB, I think this was with WinXP though. Maybe it is also a matter of ops system used?

Hey Tommy_H

I remember the post where he mentioned the 3gb usage as well. But I'm inclined to believe that was his total system memory usage and not the Oblivion.exe process memory usage as most users I've spoke to in the past always mentioned that there Oblivion process never reaches above 1.7gb or so.

As for Purging the Cell Buffer, I'm using one as well. So either it isn't doing it's job properly, or I have another mod with a memory leak currently loaded that is exceeding the purge functionality from regulating memory usage adequately.

I'm currently using... http://www.tesnexus.com/downloads/file.php?id=27009

I've just got back into Oblivion after a long abscence and using 250ish mods(some of which are quite heavy such as OOO and RAEVWD(full package)) plus a lot of texture replacers and i haven't had any CTDs or stutters even when my ram usage exceed 1.8-1.9 gigs on WinXP 32 bit thanks to OSR.

EDIT:oops i forgot to mention i'm using Streamline with only streampurging enabled and default Oblivion.ini.

Excellent news Windfang! I have a couple follow up questions...

Can you estimate what your longest continuous game session has been?
Are you using any method to purge the cell buffer?

Interesting that you are using 32bit WinXP.

Yep edited post just after to say i use streamline3.1 beta with only streampurging enabled to clear buffers.

As for longest continual play time? Maybe 5 hours yesterday and then i had to switch off and do things IRL. Bear in mind my characters play time is only about 50ish hours but i haven't had 1 CTD yet.

Well, I stand corrected. At least anything related to the game is concerned. However, I'm still curious about your 32bit WinXP. I would love to hear a player with my OS comment on there performance.

I should maybe add that I am also on WinXP 32bit still, I have 4 GB RAM installed.

I am using http://www.tesnexus.com/downloads/file.php?id=9139 mod. I've set it to purge on every third loading screen, which is somewhat less frequent than default which would purge on EVERY loading screen. It seems to do the job, but I can't say if it's any better than LazyPCB, Streamline's or even Kuertee's AutoSave and Time, which also offers a PCB function.

There's a couple of people in the hardware forum who appear to have similar issues with memory usage reaching 1.7GB. At least one of them is using Windows 7.
http://www.gamesas.com/bgsforums/index.php?showtopic=1075717

First: When the game crashes for me, it's nearly always due to being out of RAM. I check task manager and almost always find it at 1.9GB+. WinXP/SP3.

Second: Keep in mind that PCB is only minding the VRAM buffers. Regular memory is what's going to get you eventually. Yes, the game or engine has leaks. The more mods you have, the likelier you are to crash sooner.

Folks able to play 5 hours in a single session are rare from what I see.

Oh!!! I'm a bit disappointed to hear that, I actually thought it would flush the regular RAM. Is there any tool for that? (I guess not, otherwise someone would probably developed it in the last 4 years...)

Very interesting. I'll link to them to this topic as well to see if we can't exchange some info.


Yeah, you feel my pain then Arthmoor. Curious though, when I run PCB with task manager open, I do see that the memory usage for Oblivion.exe does decrease, so not sure if it is only purging data from Vram, it looks like it's purging both to me. Correct me if I'm missing something.

Hmm. I'll have to check it again, but I don't ever recall regular memory dropping when a pcb was called before.

Well, I think if the VRAM on the card gets over-full, the card will start loading off graphics information into the regular RAM, which of course in not ideal because the swapping back and forth takes long time over the bus. So I would not be surprised if some of the RAM usage is from the video card, especially if you have a card installed with a small/smaller VRAM.

@Arthmoor - Yeah, just be sure you are checking Oblivion.exe process. You should see it drop.

@Tommy_H - I could see how running low o Vram would cause issues. So far I am ok with Vram for now as I rarely exceed 800mb. I should have 1024mb to spare. For others though, it's definitely something to consider.

I know that Windows7 changed the way it allocates memory for graphics etc... I'm going to research a bit more on this as I am under the impression that I may be running out of free memory because it is allocated for backup Vram instead of physical usage for programs. I can go more into later. Gotta get some sleep for now.

Use the RivaTuner tool to see how much GPU memory is stored in the System Mem.
Currently I have not a fully Oblivion ready system to give you all the info you need.
But from experience I know you can push the total system mem used far up 2G.

1.I had crashes on my test run when i was checking to see just how much of your fabulous RAEVWD mod i could get away with installing before my VRam got saturated and my GPU started crapping out on me and a few meshes that got corrupted when Pyffied. Once i started a new character on my proper run i've never had any problems with high ram usage. Seems for me Vram usauge was more of a problem than regular ram.

2.Really? I don't doubt what you say but when i was doing my test run i had Rivatuner running in the background so i could get a log of my Ram and VRam usage(I remember someone saying in the forum that the console doesn't really report an accurate values) and i noticed Ram usage fluctuating by as much as a GB. Probably when i was in entered and exited towns and dungeons. If i'd been thinking i should've wandered about about for an hour or so and returned to my starting spot and checked the difference in my initial ram usage and final usage but :shrug: . I wasn't having problems so it never concerned me.

3.Yep. I keep my hardware clean and well maintained, OS heavily tweaked and free of as many start up programs as possible, up-to-date drivers, BOSSed loadlist with final hand tweaks, Bashed, pyffied meshes, tweaked OSR and use streamlines' streampurge only and i'm pretty certain if i used another medium mod my PC would start CTDing regularly on me.

Like you said i'm one of the lucky ones but i wasn'talways so in the past.

Oh and for anyone who wants to know my specs
C2D E8500 oc'd @3.81GHz
4GB PC 8500
Asus P5K premium wi-fi black pearl
GTX 280 with 1GB Vram(stock speeds)
Creative Soundblaster Xtreme Gamer
1GB Western Digitial Black
Windows XP 32-bit SP3

Can't post modlist since i'm not on my home ATM.

Wow, I've been testing for over a month and through my tests I've came to some of the same conclusions... weird how people come up with some of the same ideas around the same time.

Here is a link to where I talked about my testing:
http://www.gamesas.com/bgsforums/index.php?showtopic=1075204&view=findpost&p=15640992

From my tests it seems to be a very good way of finding out just how long you will get on a given mod setup. The more mods you add the less stable Oblivion gets because the more memory you use. But I think there might be something more to that. I know that skyranger is working with the hash tables in the game and OSR is trying to optimize them. Now I'm thinking mods like MMM or OOO... or really any mod that adds lots of new items, creatures, etc. Bloat out the hash tables to a point where oblivion just cant handle it any more or maybe even exposes a preexisting memory leak to stress that then causes the game to prematurely crash.

My crashing typically starts not because I added 200 mods but because of the type of mod I added. More creatures and Items guarantee a much earlier crash.

My system specs are as follows

C2D E8400 OC'd @3.9Ghz
2Gb PC2-6400
EVGA FTW
2x BFG Geforce 8800GTX Factory OC (Just a little less then a Ultra spec wise)
Creative X-Fi XtremeGamer
2x WD Raptor 74Gb Raid 0
Windows XP 32Bit SP3

like Windfang my system is very well maintained.

The crashing is predictable and reproducible within the parameters of the test I created. On average I can expect crashing around 1350 BsTasks with a basic FCOM install. With MMM its usually around 2000 or there abouts. With no mods that add new creatures or items I can get around 3000. With vanilla I can get around 4000. I've ran that test I mentioned over 20 times in the past week alone. Very reliable and consistent results. I typically translate those numbers into between an hour and two hours per 1000 BSTask count under normal playing conditions. So under optimal conditions you could conceivably get up to 8 hours on a game with vanilla.

I've suspected an engine issue for a while now but I'm under the impression that there is little that can currently be done about it. Unless skyranger or someone like Windom Earle can rework oblivions guts and plug some holes with an OBSE plugin. I kind of doubt it can be done though, cuz its going to take some 1337 Crazy haxor skills man lol

On a side note... I haven't ran a test while in window mode to see the memory during testing... I'll shall have to try that. I'd bet the BSTask count closely mirrors where the Memory is and where it crashes.

That was me. Oblivion ran for several hours before crashing. When it finally crashed, Task Manager showed Oblivion.exe using 3.6 GB of RAM. That was the only time I've ever seen it using that much RAM. It was always before crashed for me long before using that much; usually around the 1.8-2.0 GB area.

This is on Vista 64-bit with 4 GB RAM.

I don't see how that is possible, as Oblivion is a 32 bit program. Even running on a 64 bit OS, it's only designed to use a maximum of 2 gigs of RAM. I'm pretty sure you were reading something wrong there. The 2 gig limit would explain why you see crashes at that point, crashing is a common result of hitting the RAM ceiling.

I did apply the /LARGEACCESSAWARE flag to Oblivion.exe, allowing a 32-bit application to use up to 4GBs total.

My system's total RAM was loaded at 98% used, with Oblivion.exe using 3.6 GBs of it. I should have taken a screen capture of Task Manager; I wouldn't believe it either unless I saw it myself. It only happened once, though; I was hoping it would be a prelude of things to come. . Maybe it was due to a serious one-time problem with the executable or something.

There?s a 4Gb enabler that works well. I don?t have the link right now, but I personally found it in one of Skyranger~1?s recent threads, in first post, so it?s not a hard catch.

I don't know why you would see Oblivion crashes for some people at 1.7 GB, but my first guess would be:
If that does not count reserved but uncommitted address space (which I believe is the case), possibly 0.3 GB of address space is getting reserved for something that never gets committed. Then, the rest of Oblivion would have 1.7 GB maximum committed memory before it ran out of usable address space. Alternatively, if some or all allocations that Oblivion wanted to do could not be done in fragmented address space regions, then the vanilla heap might render a few hundred megabytes unusuable due to its rather odd patterns of address space usage that tend to fragment the remaining address space around them.

I'll look into the options Riva Tuner offers. I think the 4 gig patch posted on
my first post should provide the same function, though i could be wrong.

This is some very good research. I wouldn't be surprised if the two are related as well.
I may have to turn on logging with OSR to get an idea if the physical memory usage correlates with
the hash tables.

This just boggles my mind. I would really love to know the configuration of your OSR etc... that provided such stability.

I have it linked on the first page of this thread. :thumbsup:


@Skyranger-1 you have no doubt have dug much deeper these sort of things than most of us.
I will keep testing to see if I can provide better details. Thanks for the improvements you've brought to
OB thus far.


I'll be uploading a video that shows the crash take place at 1.7gb. I will also be posting
additional videos, all with different variables that should help add stability to the memory ceiling
that seems apparent.

You missed one possibility. There's a problem with one of his cards so the game crashes as soon as it starts to get into the corrupted address space.