Oblivion And Memory Usage
Prevent CTDs from heavily modded games
http://www.gamesas.com/bgsforums/index.php?showtopic=1076274&st=0&start=0

UPDATES: An important discovery for those who still experience a 1.8gb memory ceiling after applying the 4gb LAA patch...


It's highly suggested for all who are interested in using the 4gb LAA patch to read http://www.anandtech.com/printarticle.aspx?i=3034(Thanks to tajikhan for digging this 3 year old article from the grave. Also, thanks to gothemasticator for suggesting it's addition to the OP.)
=============================================================================

Past Updates:

So, it's confirmed that the 4gb LAA patch does not allow Oblivion.exe to use more than it's 2gb limit of physical memory on any 32-bit OS. The 2gb limit is actually closer to 1.8gb on most machines. With the exception of a 32-bit OS with 4gb of ram installed, 1.8gb would be the highest amount of memory a player can expect there Oblivion.exe process to reach before it experiences a CTD. (This was tested on fresh installs WinXp/Vista/7 32-bit in 2gb and 4gb amounts. Memory Ceiling CTDs can vary depending on the amount of RAM the OS and other programs are using during the time Oblivion.exe is running. Some 32-bit OSs with 4gb of ram installed may reach up to 1.95gb on a higly efficient Windows 32-bit memory cleanup.)

* 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 can cause additional stutter and lag.)
=============================================================================

Important Reminders

* Please be aware that the patch listed on this page may produce undesirable results if used on an altered or modified Oblivion.exe file. This may include loading the game from a virtual drive.

* An important reminder to 64bit 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.)
=============================================================================

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...
=============================================================================

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.

=============================================================================

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 - 1.8gb 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)

* Please be aware that the patch listed on this page may produce undesirable results if used on an altered or modified Oblivion.exe file. This may include loading the game from a virtual drive.
=================================================================================

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 64bit 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.
=============================================================================

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?
=============================================================================

LAA generally has little or no effect on VRAM issues.

There is apparently a flag for directx textures that creates a backup copy of the texture in RAM, and on some version of windows the backup copy is stored in the processes address space (and thus effected by LAA), on other versions of windows it's stored in a separate address space. But Oblivion does not use that option. Or that's my understanding.

So, will my 6 GB RAM system with 1 GB ATI Radeon card benefit from this patch or not?

Yes of course, just not the vram part.
But RAM usage will be able to go up to 3.8 Gb instead of 1.8 Gb.

edit:
And so delay crashes because of lack of memory.

Dually noted SkyRanger-1

My reason for including VRAM in the topic this time around was because LAA increases the amount of system memory that Oblivion can make use of, correct? If a player exceeds there VRAM dedicated amount, system ram will be used as VRAM. (Or atleast that is what we have learned from Win7/Vista tests) I know this happens with or w/out the LAA patch, but my point is we have a lot more system memory that can be utilized. Whether this can be stable or not is still under testing. So far, the stability hasn't impressed me.

EDIT - My hope is we can continue discussions to think of why it is unstable and if there is a way to add stability.

Actually if the VRAM usage exceeds the total I don't think it takes memory from the process memory but system memory, ie you won't see it in the total memory usage of Oblivion.exe.
LAA will only change the space accessible to the process, not the drivers behind it(it's the graphic card driver that requests system memory if vram is exceeded, not oblivion).
I already made that point in the previous thread.

Hmm, I'll need to keep an eye on the system memory rather than the process memory then. You might be right with that. I know you made a similar point in the last thread, although worded quite differently. I was under the impression that your last comment was a bit more restrictive. Your point is much clearer this time.
Although, take a look at the VRAM usage video I posted. There is a timeframe between 1:20 and 1:45 that shows dramatic increases in both VRAM and Oblivion.exe process memory simultaniously. It looks to me that VRAM is getting cached under the Oblivion.exe process. Though I could be wrong...

EDIT - Wait DarklyDreaming, I think we are mis-understanding each other. I understand that system memory is what gets used for additional VRAM. I understand that can happen w/ or w/out LAA. I think I am looking at this narrowly based on my own hardware setup... I have 1gb of VRAM. In order for me to exceed that 1gb VRAM and remain stable so that my Oblivion.exe process doesn't hit the memory ceiling of 1.8gb, I require the LAA patch. If I didn't have LAA enabled, I would crash very quickly, because my Oblivion.exe memory process would be around 1.7 - 1.8gb right around the time I start to exceed my dedicated 1gb of VRAM.

For other players who have less VRAM, LAA would probably not be required if they want to try and exceed their dedicated VRAM. Chances are they would still have quite a bit of allocated memory left to be used for the Oblivion.exe process. It obviously differs on what cell you are in the game and what mods you have loaded.

Sorry for the confusion.

As DarklyDreaming said, 3.8 is the limit with the LAA patch for allocated Oblivion memory use.
I have shown that VRAM can be exceeded to a point where system ram will be used for VRAM.
So yes, you can go over your 1gb dedicated VRAM amount, mostly because LAA will push
your memory ceiling up to 3.8gb from where it would usually crash at 1.8gb. So now with all of that
extra headroom, you could go crazy and add large texture mods and increase past your 1gb VRAM.
However, the problem I have encountered is that Oblivion does become unstable once you have gone
past your dedicated VRAM limit up to a certain point. I'd say you are safe if you remain within 100mb-200mb over your VRAM limit,
but until more testing is done, it's hard to say at what amount above your dedicated VRAM where Oblivion will begin to fail.

EDIT - You may even be able to go past your 1gb of VRAM w/out using the LAA patch, but just watch out that you don't exceed 1.8gb
on your Oblivion.exe memory process, or you will CTD.

I'll know more later in the week. :goodjob:

System ram is massivly slower then VRAM, so once you start using system ram to make up for lack of VRAM your frame rates will tank. Then all the scripts that have to process on a frame end up running much slower too. So my guess would be that this could cause things to overload and cause crashes. Stutter remover may or may not help with this, best case you will end up in "slo mow" with actors and everything else running that way, assuming you are allowing stutter remover to do this for you. Basically running out of VRAM is bad, you don't want to do it, even though you can.

I 100% agree with your post and can attest to the noticeable stutter and lag that happens when you exceed past dedicated VRAM and move to using system ram.
We went into these details last thread, but never really made any 100% for sure answers. For myself, I just concluded that it is best to stay within your dedicated VRAM. This is on the OP. Thanks for the further details regarding how scripts behave per frame etc... That was not brought up in the last thread. Really brings even more reason to just stay within dedicated VRAM for stable, smooth gaming.

So I'm unhappy to report that this didn't work at all. Vista 64 bit. 4 gigs system ram. Game crashes every time I hit 3.03 gigs used total, which corresponds to ~1.8 gigs of game memory.

Any thoughts?

Actually, I haven't tested on Vista 64 yet. I don't see why it shouldn't work though.
You are sure that you applied the 4gb patch to your Oblivion.exe file located in your Oblivion folder, correct?
It can't be applied to a shorcut. Also, double check the notes that are mentioned in "The Fix" section of the OP

Positive. I've already double checked the notes. Been testing this for an hour and checking it with mod-specific possible crashes. Didn't work.

I just noticed this wasn't under The Fix section like I thought. I must of deleted it some how.

* Please be aware that the patch listed on this page may produce undesirable
results if used on an altered or modified Oblivion.exe file. This may include loading the game from a virtual drive.

I'm not loading the game from a virtual drive, and I'm not experiencing undesirable effects. I'm experiencing no effects. I ramped up the number of mods I'm using with a new game and a brand new bashed patch to see if it works.

Doesn't work. Consistently crashes at the old ram ceiling.

Do you see a Oblivion.exe.Backup file in your Oblivion directory? This should of been created if your patch was applied successfully.

EDIT - Are you monitoring your Oblivion.exe process during the game? You mentioned your total memory usage was 3.03gb, but sounded as if 1.8gb was an estimate off of your total. It's important that your Oblivion.exe memory process is crashing consistently around 1.8gb.

Follow these instructions...

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.


If you are still getting crashes consistently at 1.8gb after watching your Oblivion.exe process while playing let us know.
Otherwise, if the CTD is not consistent, it may not be relative to a memory ceiling issue at all.

Yep.

I was getting my Oblivion memory usage from the amount my ram usage dropped after I killed the process. But I fixed the problem by deleting the oblivion stutter remover script. I've now ramped my mod count back up, and it seems to work. No idea why it was casuing the problem.

what version? Any details you give would be helpful

You can get a 32-bit OS to use use up to 3gb with a hack.

For Windows XP you have to add a /3GB switch to the BOOT.INI file.
For Vista you have to type in BCDEDIT /set increaseuserva 3072 from the command prompt.

The big problem with this hack is that it will restrict the amount of memory available to the kernel from 2gb to 1gb! So Oblivion will be able to use some extra memory but the rest of the system will be starved for memory.

Do a search for the 3gb switch for information on the subject.

thanks for giving a bit more insight on this than others have. by the sound of it, 32 bit users could efficiently clean there memory use of there OS enough to add more ram for oblivion and still keep there OS stable.

As was said in the previous thread, use of the /3GB switch is not recommended because many drivers become unstable with it. On my computer Oblivion seems to work okay with it, but Vampire: Bloodlines had severe trouble.

deconite: Was heap replacement enabled? If so, what was your iHeapAlgorithm and iHeapSize?

And just to toss my 2 cents in, the /3GB switch destabilizes my entire machine regardless of anything that gets attempted. The LAA flag means entirely nothing if the OS itself is barfing up BSODs.

The version linked. My system's kind of weird on its own. I have such a large number of mods it's possible the buffer cell purge was affecting some data that was later being called up or some such crap.

It was enabled but I dont' remember the size. I'm pretty sure I didn't alter the size from the default, or if I did I did it to instructions that came with it. I deleted all that stuff in a rage, (along w/ some other things, heh) so i can't actually tell you what the number was.