Question about Memory Usage

[Draiden]

Hello, I am new to forums, and somewhat of a newbie when it comes to technical matters. I have about a question about the concepts of memory terms that I find under "System Summary" within the 'System Information' program.


System Information: Memory

Above is a screenshot of what the System Information program says about my Memory.
[new edit] Apparently, the screenshot is picky about when it wants to show itself to anybody else!
Here's the info:
Total Physical Memory: 512 MB
Available Physical Memory: 212.90 MB
Total Virtual Memory: 1.72 GB
Available Virtual Memory: 1.18 GB
Page File Space: 1.22 GB

My question is, why is my available physical memory lower than my total available memory, and is there any way to make more of my available physical memory available? What is Virtual Memory, and why is it higher than my physical memory, and how does its size relative to the size of my other type of memory affect my computer's performance? What is a page file and how does its size, relative to the two types of memory, affect my computer's performance?
I ask these questions because I want to know how I can improve my system's performance, but doing search's on these topics on the net returns forum threads I don't understand. I found a thread on these forums about page file size and adjusting it, but I didn't understand what was being talked about, so I thought posing my own questions asking for simpler answers would be more helpful, not only for myself, but for other newbies too.

Thank you very much to everyone who replies to my post, it is very good of you to share your knowledge (in layman's terms, please? = P) with us.

 

[Rick]

Physical memory - RAM

512MB is a nice amount to have in a good performing system. If you would like to increase your physical memory, then you will need to upgrade your RAM.

Virtual memory - Page file

The pagefile is basically emulated memory on your hard drive. It is much slower, but used by many programs and also useful when you run out of physical memory.

 

[Draiden]

Re: Memory Usage

Thank you Rick = ) But the main thrust of my question is to find out why so little of my total physical RAM- less than half- is actually available? Why is it that only 212.90 MB out of my entire 512 MB of RAM is available? Can I make more of my existing total physical ram available? How?

 

[Rick]

Well, Windows XP itself accounts for well over 120MB of that total. I've noticed Windows behaves differently depending on the amount of memory you have.

The rest are probably applications that are running in the background. You will also "lose" memory as you use your computer. THis memory will be freed as needed by Windows. Some people use memory management programs to free up memory, but I personally think they are a placebo.

 

[Intacepta]

Hi,

I have a laptop with 256mb of RAM but only 224 mb shows up. I also have a motherboard with onboard graphics which shares a specified amount of memory with various other processes. This may be happening in your case. Check to see if you have onboard graphics and if so enter the system BIOS where you should beable to modify how much RAM it shares.

Ollie.

 

[wizard_morton]

Interesting question, I don't know if your virtual memory space and page file space are different but mine are, I also am somewhat of a newbie to forumsbut have a little experience of the whole affair but, my question is WHY?

 

[Tedster]

oooph! 256mb of memory? Man you need to get more memory NOW! Get at least 1mb for a laptop. With laptops memory is not only critical but is saves a lot of time and battery power as your hard drive will have less work to seek files.

Windows XP eats an enormous amount of memory around 140mb.... this leaves little for other stuff and if your graphics chip eats another 16 to 32mb of memory you really don't have squat left.
get more memory!!!!

 

[Didou]

Did you guys really need to reply to an 8 months old thread ? The person who asked that question probably doesn't visit here anymore so it's not like he'll see the answer anyways. :blackeye:

 

[Tedster]

didn't pay attention to the date.... but oh well... someone might read it! you did!

 

[Blakhart]

"My question is, why is my available physical memory lower than my total available memory, and is there any way to make more of my available physical memory available?

As said before, xp takes around 120 off the top for itself. This is typical.
Then you have the system cacheing that goes on, and it takes up a lot more if you have the system up for more than a few hours, opening and closing apps. See xp will keep stuff cached in mem just in case you fire that app up again that you had used earlier. This cacheing speeds up app loading. If you fire up a new app that needs all the available mem, it will get it as the cached mem will be flushed for that app to use. Using the always unload dll hack to "get back" memory can lead to trouble, so don't bother with it. The best way to have plenty of ram available is to watch what processes are running, reducing same if need be, and maybe disabling/set to manual certain services that are not critical. That is: if you have a finite amount of ram, you can only reduce ram usage. You must reduce apps in size or number.

"What is Virtual Memory, and why is it higher than my physical memory, and how does its size relative to the size of my other type of memory affect my computer's performance? What is a page file and how does its size, relative to the two types of memory, affect my computer's performance?"

Everything in memory has a seat saved in virtual memory on disk, although some things are never written to virtual mem/pagefile, such as most of the kernel of the os. There has to be enough space in the pagefile to hold pretty much everything in memory at any given moment. There has to be enough space in virtual mem to hold a memdump in case of a crash, too. This means that usualy you will have a larger pagefile _availability_ than your memory total, but not all of it will be in use. And as you've seen, the available memory is larger than youre total ram. Hmm wonder why? That's because your pagefile is included in that figure. Typicaly M$ sets a pagefile size with the 1.5x total ram arithmetic. Pagefiles are pretty well best left alone, and left dynamic so they can resize if they have to. If you run out of pagefile space for whatever reason you will probably crash. Some apps absolutely require a pagefile, too. Even if you disable pageing the os still pages as it is designed to always do so, always. It just makes a pagefile behind your back. Keep this in mind: NT (NT, 2k, all vers xp) was designed to page. Let it.
When you haven't used a portion of a program for a while, but it is still running, that unused portion gets paged to the hard drive to make room for other apps in real memory. Get it?
Now if you don't have enough mem to run a program outright, xp will fake it by using paging to get by. See, xp tells every program it has 2gigs of memory it can use. Even if you only have 256m real mem.
Here's the rule on memory/paging performance: always have more ram than your apps will ever need under most circumstances. Or, "fit the app to the available ram." If the app is huge, you might want to find a lower resource version of that app. This reduces paging to a bare minimum. We do this because paged data access is very slow compared to ram access of the same data.

XP: Hello Mr App, what do you require?
App: Hi, can I have 128m ram?
XP: You can have 2G!
App: Wow, cool, thanks. I'll only take the 128 tho.
XP: (to self) hmmmm what am I going to do since I only have 98m ram left? Ah yes, pageing! How sneaky of me!
App: (is none the wiser)


Bonus question: How do apps/services get into memory in the first place?
Answer: Paging!

Just some thoughts on the subject.