Memory used by games

[DaveM]

Hi All,

I have a gaming PC which is about 2 years old. It has SLI 980ti's 16Gb RAM and an SSD for the OS (win8.1).

I've always wondered when playing any AAA game title why it can never use the amount of RAM on my machine to the fullest.

Most games seem to to top-out at <7Gb of RAM

 

For example, why can it not load the current and next game levels into memory and just page to these rather than doing a load from disk.

Doom (2016) is a perfect example with frequent level reloads from the HDD.

 

I understand that developers try to optimize for standard hardware specs, but why can't they detect and use more memory if it's available?

Thoughts?

Dave

[RAM555789]

5 minutes ago, DaveM said:

Hi All,

I have a gaming PC which is about 2 years old. It has SLI 980ti's 16Gb RAM and an SSD for the OS (win8.1).

I've always wondered when playing any AAA game title why it can never use the amount of RAM on my machine to the fullest.

Most games seem to to top-out at <7Gb of RAM

 

For example, why can it not load the current and next game levels into memory and just page to these rather than doing a load from disk.

Doom (2016) is a perfect example with frequent level reloads from the HDD.

 

I understand that developers try to optimize for standard hardware specs, but why can't they detect and use more memory if it's available?

Thoughts?

Dave

It depends a lot on if the program is 32 bit or 64 bit. On 32 bit applications only 4gb of RAM can be used while the theortical limit for 64bit is 16 exa bytes. Many games that are 64 bit do not require all the RAM you may have avable at the time and its your processor or GPU slowing your games down.  RAM is rarley an issue.

[DaveM]

I'm aware of the 64-bit architecture required for >4Gb of RAM. The original question remains: Why can't developers use available memory to speed-up gameplay experience. I.E pre-load additional game levels, pristine copy of save-game-states that can be paged to etc.

[cadd]

it would take more work for something most people cannot benefit from at the very least.

[DaveM]

Well according to the Steam hardware survey, 20% of it's users users have 4Gb of RAM, 33% have 8Gb and 21% have >12Gb.

 

http://store.steampowered.com/hwsurvey

Developers don't always (ever) listen to gamers but if reviewers started asking this question, we may seem some progress.

[GoodBytes]

27 minutes ago, DaveM said:

Hi All,

I have a gaming PC which is about 2 years old. It has SLI 980ti's 16Gb RAM and an SSD for the OS (win8.1).

I've always wondered when playing any AAA game title why it can never use the amount of RAM on my machine to the fullest.

Most games seem to to top-out at <7Gb of RAM

 

For example, why can it not load the current and next game levels into memory and just page to these rather than doing a load from disk.

Doom (2016) is a perfect example with frequent level reloads from the HDD.

 

I understand that developers try to optimize for standard hardware specs, but why can't they detect and use more memory if it's available?

Thoughts?

Dave

Well it is a bit complicated, I am sure someone else can explain better than I am, but to make it brief:

It is the game that doesn't load more stuff to RAM. Simple as that. Either they put a limit, or there is nothing to load more (as everything is loaded), or you don't have enougth video memory to matter. Remember that textures, level design, models, etc. are all loaded in your GPU memory, and data swaps back and forth between GPU RAM and your system RAM, then you have a "data fetcher" from the game engine which takes stuff from your HDD/SSD to your RAM. Usually kicks in when the game loads, or when you don't have enougth RAM, or as needed as you play (optimization trick used in large open world environments, including real world flight simulators, where they have several TB of world data map, but no loading as you travel from one area to another)

 

Also, the next level may have different shaders that needs to be compiled based on your game settings loaded, so might as well load a level then and there, textures and so on. Usually open world games like GTA, or flight simulators, takes a long time the load the first time, to compile all needed shaders which is a lot to cover all lighting areas, whether conditions, areas specific changes, graphics settings based on your graphics settings, and load main scene where you start., then you have no load screen as you move. Of course you have caveats, like slow HDDs, so it is a balancing act of how much in advance you need to load the scene, and many other challenges, but that is all engine works solved by developers of the game, where you have various solutions between developers, fitting their needs better, and what most users have as system specs.

 

[Mira Yurizaki]

33 minutes ago, DaveM said:

Hi All,

I have a gaming PC which is about 2 years old. It has SLI 980ti's 16Gb RAM and an SSD for the OS (win8.1).

I've always wondered when playing any AAA game title why it can never use the amount of RAM on my machine to the fullest.

Most games seem to to top-out at <7Gb of RAM

 

For example, why can it not load the current and next game levels into memory and just page to these rather than doing a load from disk.

Doom (2016) is a perfect example with frequent level reloads from the HDD.

 

I understand that developers try to optimize for standard hardware specs, but why can't they detect and use more memory if it's available?

Thoughts?

Dave

Because trying to hog up all of the available memory is a terrible thing to do, especially when it's not guaranteed you're going to play until the next level anyway.

[TVwazhere]

I cant believe almost 10% of steam users only have 3GB of ram.

[TheRandomness]

-Thread moved to CPUs, Motherboards, and Memory.

[DaveM]

On 17/02/2017 at 4:48 PM, M.Yurizaki said:

Because trying to hog up all of the available memory is a terrible thing to do, especially when it's not guaranteed you're going to play until the next level anyway.

Not all of the available memory but I'd like to able to specify to the game to use up to 90% of system memory instead of <50% it is currently using.

Thanks for the reply @GoodBytes.

Take a case in point  - Doom.

On the difficulty setting I'm using, the game only saves at checkpoints seldom throughout the game.

Each time I die (which is a lot), the game reload this checkpoint from disk. Why can this savegame not be stored in memory instead?

The game could also write a copy to disk for obvious reasons,

[Mira Yurizaki]

6 hours ago, DaveM said:

Not all of the available memory but I'd like to able to specify to the game to use up to 90% of system memory instead of <50% it is currently using.

Thanks for the reply @GoodBytes.

Take a case in point  - Doom.

On the difficulty setting I'm using, the game only saves at checkpoints seldom throughout the game.

Each time I die (which is a lot), the game reload this checkpoint from disk. Why can this savegame not be stored in memory instead?

The game could also write a copy to disk for obvious reasons,

Check points are either stored in memory or are small enough that loading them is fast despite being on a hard drive or SSD. What's causing the "loading" is that the game has to re-initialize itself to the state that the game was in.

 

Loading is more than "move stuff from storage to memory", it requires processing to initialize and setup the application for use. In fact, a fast enough processor with an HDD can match the loading times in some applications than a slower processor with an SSD.

[DaveM]

On 19/2/2017 at 2:03 AM, M.Yurizaki said:

Check points are either stored in memory or are small enough that loading them is fast despite being on a hard drive or SSD. What's causing the "loading" is that the game has to re-initialize itself to the state that the game was in.

 

Loading is more than "move stuff from storage to memory", it requires processing to initialize and setup the application for use. In fact, a fast enough processor with an HDD can match the loading times in some applications than a slower processor with an SSD.

That seems strange to me. At the end of any initialization process there are memory contents, cpu registers and GPU memory contents unless the game has a network component which may make the content time-dependent.

Why cannot the output of this initialization process not be stored once or twice in memory. The game could then just page between copies.

[dragoon20005]

here is what i have noticed

 

games which are for many platforms like the Xbox 1 and PS4

 

those game consoles have only max accessible up to 5GB for the game and 1GB for the OS and up to 2GB for VRAM

 

so yea games which are ported from consoles will still have the RAM usage limited to around 5GB even with PCs with 16GB or more RAM

[Mira Yurizaki]

5 hours ago, DaveM said:

That seems strange to me. At the end of any initialization process there are memory contents, cpu registers and GPU memory contents unless the game has a network component which may make the content time-dependent.

Why cannot the output of this initialization process not be stored once or twice in memory. The game could then just page between copies.

Because you would be holding a saved state. If the game I was playing consumed 6GB of RAM at the time of some checkpoint, it's going to have to store 6GB of data to store that state in order to have "instant" loading times.

 

5 hours ago, dragoon20005 said:

those game consoles have only max accessible up to 5GB for the game and 1GB for the OS and up to 2GB for VRAM

I don't think that's the case considering this:

 

This is from https://www.guerrilla-games.com/read/killzone-shadow-fall-demo-postmortem

 

If you add that up, you'll notice only ~4.5GB of RAM is used by Killzone: Shadow Fall.

5 hours ago, dragoon20005 said:

so yea games which are ported from consoles will still have the RAM usage limited to around 5GB even with PCs with 16GB or more RAM

I've seen Deus Ex: Mankind Divided eat up 6GB of RAM.

[DaveM]

Quote

Because you would be holding a saved state. If the game I was playing consumed 6GB of RAM at the time of some checkpoint, it's going to have to store 6GB of data to store that state in order to have "instant" loading times.

I'm not sure I understand you here @M.Yurizaki

Do you mean 2 copies of the 6Gb game in memory?

If so, and I have 16Gb of memory; I don't see a problem with this.