Page file fills up while RAM is not full, why?

[Tom]

Hi,

I work on a scene that takes around 40Go of RAM while loaded in 3ds Max.
I have 128GB of RAM. After I've done few interactive renders, and worked a bit on the scene, by adding/modifying objects etc ... I can see that pagefile.sys on the system drive fills up to 10GB. When windows starts this file is only 0.8GB.

Why does pagefile.sys fills up whereas there is still a lot of RAM available? It does not seem very efficient. I would expect pagefile.sys increase only when there's no more RAM available.

Thank you for the help,

[TomG]

RAM used when loaded is not the same as RAM required while rendering. You can add a pretty detailed set of memory breakdowns in the Render Stamp, head to the system tab of the render settings, click the ? to see the list for things like %mc Memory used by Corona, %mcp Peak Memory used by Corona, %mpp Peak Virtual Memory Used by Max + Corona etc.

[Tom]

Hi TomG,

Thank you for your support.
The options you mention are very useful indeed.
But I still don't understand why pagefile.sys fills up while the peak virtual memory used by 3ds Max + Corona is 69GB, and the virtual memory used by Windows is 102GB. All these values are less than my total amount of RAM which is 128GB, so why does windows fills up the pagefile.sys?

[dj_buckley]

Sorry to resurrect an old thread but I have a similar question.

I've dramatically reduced the size of my page file recently due to the fact I have 128GB RAM.  It was taking up 60GB of space on my C:Drive so I assumed I didn't need it to be that big as I now have the RAM capacity to deal with most scenes.  But now every time I render I get a Bad Allocation message.

So my question is.  How big should the page file be with regards to rendering in Corona?

[Tom]

Hey,

It is still a bit mysterious to me as well, but what I can tell you is I'm fine on most scenes with a 800MB pagefile.sys.

[Juraj]

It's not advisable to fully disable page file, almost regardless of physical memory amount. Windows is pretty much designed to put some (usually system) files there.
How Windows allocates resources can get rather mysterious, but fully disabling it on Win10/11 can get crash-prone.