How to reduce ram below what is physically installed

I have 32GB ddr4 (2x16) and want to make only 8GB available to the O/S. Is this possible? I want to see how well win11 performs with only 8GB

If you're not doing that inside a VM, you have to physically remove all but the 8GB you want to test. You can't tell the OS, ignore some.

I would advise setting up a VM of Windows 11 and set that to 8GB and you'll be able to run your tests.

Archigos said:

If you're not doing that inside a VM, you have to physically remove all but the 8GB you want to test. You can't tell the OS, ignore some.

I would advise setting up a VM of Windows 11 and set that to 8GB and you'll be able to run your tests.

Click to expand...

Wouldn't the overhead of the VM distort the results?

No, because the overhead would affect the host system, not the client (which would have the 8GB limit)

Are you running Windows 11 Home or Pro....

If Pro: Enable or Disable Hyper-V in Windows 11 Tutorial
If Home: Use something like VMWare, VirtualBox, or similar

pro

When I used to run VM's the O/S was always slower than a physically installed version so I don't think it would simulate an 8GB system accurately.

The system I have now started with 8GB, I did end up upgrading to 16GB, then 32GB later... but the Windows 11 Pro installs I run in Hyper-V with 8GB actually run FASTER than the system did when it was a true 8GB system.

Hmmm, I never tried Hyper-v, just vbox and Oracle. Will give it a shot. Thanks!

When did you 8GB install start slowing down?

No problem

The easiest way is to set up a RAMDisk of 24 GB but do not use it.
See @garlin method.

Using VMs is over complicated and will not give you meaningful results.

However, it is difficult to assess performance with 8 GB unless you are doing something that does a lot of pagefiling.

With 32 GB, you are probably hardly using RAM.

As a sort of rule of thing with average sort of use:

2 GB RAM - Windows will be very slow pagefiling a lot
4 GB RAM - Windows will run slowly, pagefiling fairly often.
8 GB RAM - Windows will run quite well, with occasional pagefiling
16 GB RAM - Windows will run well, with very occasional pagefiling (if any)
32 GB RAM - it will hardy run better than 16 GB RAM.

Where lots of RAM helps if you are running memory hungry apps (or zillions of open tabs in a browser)
Another use is if you are running multiple virtual machines i.e, more RAM, the more you can have open at the same time.

With 8 GB, you can really only run one VM say 4GB RAM.
With 16 GB, you can have 2 or 3.

If you are not using memory hungry apps or VMs, then you may not detect any major reduction in performance with 8 GB.

If you do a lot of pagefiling, performance will be more affected by the type of drive you are using e.g. an old slow HDD will be affected by pagefiling much more than modern fast nvme drive.

So more RAM does not generally improve performance that much but allows more efficient multi-tasking. Ultimately, performance is still CPU limited.

In other words, you can get results from "virtually no impact" to "running like a dog" depending on your hardware set up and what apps you are running.

Subtract 4 GB from physical memory:
bcdedit /set {current} removememory 4096
Reboot.

Restore all physical memory:
bcdedit /deletevalue {current} removememory
Reboot.

garlin said:

Subtract 4 GB from physical memory:
bcdedit /set {current} removememory 4096
Reboot.

Restore all physical memory:
bcdedit /deletevalue {current} removememory
Reboot.

Click to expand...

Yeah that is better than my RAMDisk idea.

I'm helping a friend select a basic desktop but they all start at 8GB. Sounds like it will be plenty for him, I doubt he ever has more than 3 tabs open lol. Easy to add another 8GB dimm too.

I generally have 3-4 browsers open with 300+ tabs and 2-4 4k monitors active which lagged terribly with 16GB on an old X6 1100t, all SSD's. Upgrading to to 32GB, and a 12th gen i3 solved everything - memory in use is < 18gb and cpu is <10% most of the time.

For some reason, msconfig doesn't work correctly in W11. Which is the expected way to stress test Windows with lower RAM.

martik777 said:

I'm helping a friend select a basic desktop but they all start at 8GB. Sounds like it will be plenty for him, I doubt he ever has more than 3 tabs open lol. Easy to add another 8GB dimm too.

I generally have 3-4 browsers open with 300+ tabs and 2-4 4k monitors active which lagged terribly with 16GB on an old X6 1100t, all SSD's. Upgrading to to 32GB, and a 12th gen i3 solved everything - memory in use is < 18gb and cpu is <10% most of the time.

Click to expand...

So you are only going to prove what we already know.

Be careful and check your friend can add RAM - a lot of laptops for example come with soldered RAM and no expansion capability. I did not know this when I bought my current laptop with 16 GB RAM!

Probably less of an issue for a desktop.

For most average users 8 GB is a good entry point - add RAM later if needed. Very few need more than 16 GB.
What is probably more important is storage type - use SSDs or NVMEs - HDDs are obscolescent technology.


PS just tested @garlin's method - works perfectly. You need to reboot after doing bcdedit for it to take effect.

garlin said:

For some reason, msconfig doesn't work correctly in W11. Which is the expected way to stress test Windows with lower RAM.

Click to expand...

Seems to work for me. Here I have set a W11 machine with 4GB installed RAM to only use 2GB of it. The unused 2GB (plus a little bit more) is now shown as Hardware reserved. Just 1.7GB is available to Windows. Rather surprisingly, it still runs quite well.

I have the problem (which is backed by other online complaints), that Maximum memory is ignored on boot, and the value is blanked.
But bcdedit works just fine. That's why I didn't suggest msconfig.

Tested with 8gb ram - zero lag with 5 tabs and office open with 4 sheets.

Opened canary with +80 tabs and it even ran well, albeit some lag switching between tabs but no more than 2 secs.

martik777 said:

Tested with 8gb ram - zero lag with 5 tabs and office open with 4 sheets.

Opened canary with +80 tabs and it even ran well, albeit some lag switching between tabs but no more than 2 secs.

View attachment 54097

Click to expand...

Which pretty much confirms what we all already know.

8 GB is a reasonable amount of RAM for average user.

I just tested my pc with 8 GB - performance was fine.

At 4 GB still pretty good.

At 2 GB it was like swimming in molasses but it still ran.

Absolutely no surprises there.

garlin said:

I have the problem (which is backed by other online complaints), that Maximum memory is ignored on boot, and the value is blanked.
But bcdedit works just fine. That's why I didn't suggest msconfig.

Click to expand...

I've just tried on another machine with more RAM to play with (32GB). You're right, msconfig doesn't work properly. First secure boot has to be turned off in the bios. Then msconfig could be set. It was not so much that it ignored the settings, more that it got them wrong. Setting 4GB ended up with 1.7GB being used by Windows, setting it at 8GB made 5.6GB available.