Is this a normal commit charge?

[Keyes]

I'm a bit confused at how this works. Currently I'm running a very demanding game - ArmA 3. Physical Memory usage is at 60%, which is just over half of my 8GB of physical ram. I have a page file of 8192MB. That would come to a commit maximum of 16GB if I understand correctly.

I noticed however as I played, the commit charge was around 90%. How would this be possible if physical memory usage is at 60%?

 

[Anak]

Just going by your figures and not quite sure my logic is correct:

60% of 8GB = 4.8GB

Plus the 8GB pagefile = 12.8GB

90% of 16GB = 14.4GB

Difference of 1.6GB that could be attributed to machine overhead so it doesn't sound too serious. Though it is possible you may have a memory leak somewhere.

You yourself mentioned, "I'm running a very demanding game":

applications sometimes use a reservation to create a large block of virtual memory and then commit it as needed to ensure that the committed memory is contiguous

Scroll down to committed memory here: http://Pushing the Limits of Windows: Virtual Memory

This reservation could be why you're seeing the 90% commit rate.


Related Links:
https://memory leak detection | msdn.microsoft.com/

http://www.sevenforums.com/general-discussion/117842-commit-charge-post1428111.html#post1428111

The Case of the Enormous Page File - Clint Huffman's Windows Troubleshooting in the Field Blog - Site Home - TechNet Blogs

 

[LMiller7]

There is a rather popular idea that commit charge is equal to the sum of pagefile and RAM usage. That is NOT correct. There is no relationship between RAM usage, pagefile usage, or any combination of the two. Any apparent relationship is just coincidence. Unfortunately many otherwise well informed sources have got this wrong.

The commit charge is a rather difficult concept to understand. Most descriptions I have seen are quite technical or wrong. Essentially it is a measurement of storage space that the memory manager has committed or promised to have available. This storage can be either in RAM or the pagefile. The commit limit is the sum of RAM size, plus pagefile size, minus a small overhead. Windows will not commit or promise more storage than it actually has available. For that reason the commit charge can never exceed the commit limit.

The commit charge is a measurement of potential storage that may be required. Typically actual usage of that storage will be less than is committed. It will often be much less.

Reserved memory is another concept entirely and I will not discuss it here. There is no committed storage for it and in 64 bit Windows 8.1 and Windows 10 it can be many TB, larger than RAM or disk size.