Windows 10 64 bit isn't properly compressing RAM like Windows10 32 bit

Hello dear community :)

I'm using Windows 10 and testing a lot in virtual machines to explore the system, and to replace some of my Windows 7 virtual machines, as some new features like the RAM compression and system file compression are really awesome. During testing, I have noticed that the Windows 10 32 bit and 64 bit version are both handling memory compression differently. Here is an example:

The 32 bit virtual machine has only 512 MB of RAM. That's below the recommend RAM value, but still working great. When the system is starting up, it is using 90% of the memory, but after a small while the memory compression kicks in and reduces everything to around 200 MB. The memory of many processes is reduced to around 4 - 400 KB, depending on the uptime.
But the 64 bit version is somehow very different. While it's also compressing memory, it doesn't really do it as good as the 32 bit version. All processes are using a lot more memory, and it seems Windows doesn't care a lot that the system hasn't much RAM available. It doesn't really compress the RAM of the processes very much, and it seems to prefer to page out everything instead. I have noticed it when Windows was complaining about low memory, as a result of my reduced page file size. This wasn't a problem on the 32 bit version due to it's great compression work.

My question: Do you have any idea why it isn't working as good as in the 32 bit version? Are there any ways, like registry values, to adjust the memory compression?

Screenshot of 32 bit Windows:



Screenshot of 64 bit Windows:



The 32 bit machine had 512 MB RAM, the 64 bit machine 650 MB. With 512 MB it looked the same. Sorry about the non-english text in the task manager.

Thanks for reading and thank you in advance! :)

It is really impossible to determine if there is a problem from the screenshots. Making meaningful comparisons between 2 computers even with the same OS is very difficult. When they are different things even more complicated. The screenshots provide a lot of detail but it isn't clear if they are of any real relevance. What is missing is the big picture, that provided by Task Manager - Performance tab showing memory information. Looking at processes is premature and often leads nowhere.

The purpose of memory compression isn't really to reduce memory usage. I wouldn't even try to explain this in a forum post. There is no real reason to suspect there is a problem with memory compression.

Thanks for your answers! I have found the cause by myself: It depends on the hard drive type. There is a massive difference when the hard drive is marked as a HDD or SSD. Once I have marked the virtual hard drive in the VirtualBox settings as a SSD, it is suddenly exactly the same like in the 32 bit version and is compressing the memory like a badass. I'm confused why the other machine was already marked as a SSD, but that's a different topic.
So, at the end I'm wondering if this memory compression behavior isn't adjustable somehow. For me it doesn't make much sense why the RAM compression isn't aggressive in low memory situations on a HDD.

LMiller7 said:

The purpose of memory compression isn't really to reduce memory usage. I wouldn't even try to explain this in a forum post. There is no real reason to suspect there is a problem with memory compression.

Thanks for this information. Anyway, it seems still very useful during my tests and running a lot more smooth than a comparable Windows 7 machine with same RAM usage.

Understand that memory compression is rather limited in scope. It does not and cannot compress memory in any process working set. Doing that would have a heavy negative impact on performance. It only works with memory that is on the modified list and at any given time there probably isn't going to be a lot of that.

I doubt there is any user control over this. If there was it would be a registry setting that very few people would be able to use intelligently. I certainly couldn't. Most people would thoroughly misuse it and blame Microsoft because things don't work the way they think they should. Understand that there is virtually nothing about memory management in Windows (or any other modern OS for that matter) that is simple.