Pushing the Limits: Virtual Memory

Im using 2 gig of ram with a 64 bit win 7 . My VM is located on a secondary drive locked at 3 gig.

Just looking for any thoughts on this type of config

My OS drive does have a small VM of 200 meg.


My dual core cpu monitor is showing 0 - 10 % max at idle with about 1 gig of ram being used.

I would say that windows 7 runs at least 30% faster than vista with a core activity reduction of about 10 -20% at idle. This is obviously based on my list of apps running which I beleive I have matched in both systems.


Cheers

Bare Foot Kid-
johngalt - I have a question here I have 64bit Vista & 64bit Windows 7 on the same HD. C:-Vista 105G; D:My Documents 40G; E:Windows 7. I can change the swap file on the Vista to a Min & Max of 7500. Windows 7 will only allow a system managed if 4137Min and recommended of 5457 (Not sure how the system sets that - Question 1)? The WEI for Vista is Processor-4.9; Memory Ram-5.9; Graphics-4.1; Gaming Graphics-3.8; Primary Harddisk-5.3==>Overall 3.8 AND for Windows 7 4.9, 5.9, 3.9, 5.3. 2.9==>Overall 2.9 --Notice the difference in the hard drive number on the SAME Harddrive? Question 2 and finally notice the difference in Gaming Graphics in Vista where ATI Catalyst Manager finsihed the install --3.8 and Vista where it wouldn't install--5.3? Question 3? - (I asked Johngalt the same question - Saw Your post and thought You might have more to say -Ok?) Thank You - God's Speed with this one --Patrick C

Hi Bare Foot Kid,

Back to the physical memory limit, I want to an old old question but I couldn't find the answer for myself. In the past, I saw an PC which run Windows XP SP 3 can reach to 4GB physical memory after we add the parameter /PAE in the boot command. But in Windows 7, even Ultimate version, they say it could support up to 4GB, but when I installed Win 7 Ultimate 32-bits version, the OS warning that usable memory is just around 3.25GB. Is that mean the rest cann't be used? and I will lost the 750 MB physical memory???

Your answer is appreciated.

Fat Bear.

I'm new to 7, but what I'm encountering doesn't make any sense to me. Hopefully someone can point me in the right direction. I have a new pc with W7, and 8 GB of ram. I installed my Photoshop Elements and tried to run it and it is saying I don't have enough virtual memory. Ironic to me since i've run the same program on older pc's with far less actual memory. Any ideas?

vballin said:

I'm new to 7, but what I'm encountering doesn't make any sense to me. Hopefully someone can point me in the right direction. I have a new pc with W7, and 8 GB of ram. I installed my Photoshop Elements and tried to run it and it is saying I don't have enough virtual memory. Ironic to me since i've run the same program on older pc's with far less actual memory. Any ideas?

Hi Vballin,

You running the 32bit or 64bit version of Windows 7?

Steven

This subject is a little more complex than what's being explained here. Let's use 32-bit.


Windows allocates PHYSICAL memory in 4K blocks. VIRTUAL memory can be allocated in any size but whatever the aggregate size is, it will POTENTIALLY be backed in REAL physical memory only WHEN it is actually populated with some data/code.



Using Task Manager

Each process you see in Task Manager resides within a 4 GB address space. This (and EVERY OTHER) address space is comprised of VIRTUAL addresses 0x00000000 to 0xFFFFFFFF. (0 thru 2^32 - 1).

Let's say you have notepad.exe AND wordpad.exe both open. EACH will reside in its own 4GB address space and EACH will have a virtual address 0x0 or 0x1234 or 0xABCD, etc. But, not all virtual addresses may contain INFORMATION (data or program code). That depends on what that application does.

Windows maps each address space's VIRTUAL memory to REAL/PHYSICAL memory on your PC. Let's say notepad.exe is a load module that is 64K in size. Let's say that MOST of the code that you use when you are using notepad resides in virtual address 0x1000 to 0x1FFF. The term "working set" refers to the NEEDED pages for a given address space. Meaning, of the 64K of code (comprising 16 4K pages, 16x4=64K), only 4K (1 page of PHYSICAL memory) is needed at "this" point in time of your using notepad.exe. Working Set is a selectable/viewable column in Task Manager. Select it and other MEMORY-related columns and compare.

Let's say you now open photoshop and open a monster 4G-size photo. Windows will toss out (i.e. PHYSICALLY write PHYSICAL memory pages to the page file) oldest pages FIRST. These would be notepad and wordpad (you had both opened per above). You now go BACK to notepad leaving this photograph open. Now, Windows must move (page-out) some PARTS (4K pages) of this PHOTO OR PARTS (4K pages) of photoshop code ITSELF to make room for that 0x1000 - 0x1FFF page you need to do your notepad stuff.



Page File

The Page File is neither virtual nor physical memory. It is simply a secondary place to store REAL physical memory pages that have been backed on behalf of an address spaces VIRTUAL memory usage AND since Windows needs more physical memory since ALL 4K pages are in use, he must write SOME portion of the physical memory somewhere. The Page File is an extension of PHYSICAL memory, not of "virtual" addressing memory. Physical memory is the BACKING for virtual memory requests (loading a program exe or dlls AND/OR user data).


Pictures would help with this immensely.

64 bit

No I'm not getting an error about discs. The error reads as follows:

"Could not start Adobe Photoshop because the volume Windows is using for Virtual Memory does not have enough free space, which could lead to stability problems. See Windows Help for information on increasing available Virtual Memory."

Now that I've actually read it I might be better able to solve my issue . . . might.