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Sunday, March 20, 2011

Setting Virtual Memory Size - Don't Forget the Basics!

“Fundamental progress has to do with the reinterpretation of basic ideas.”
Alfred North Whitehead

Recently, I was returning to my office having retrieved yet another cup of coffee, when Nicole Morris, one of the KETIV team members, said to me. "Virtual memory still matters."

Naturally, this puzzled me for a moment.  Of course the statement seemed "out of the blue", but then Nicole explained her seemingly random statement.

She had been working with someone who was having problems with performance on a really large assembly.  The computer was sluggish for some reason, but the system had 12GB of RAM, plenty of processor speed, and a video card that would have made the typical geek drool like a Labrador Retriever.

The Virtual Memory was set wrong.  Nicole explained that they'd set the virtual memory to 1.5x RAM, and the computer began singing like a song bird.

"No kidding?"  I say, surprised (Okay, I've substituted "kidding" instead of the actually word I used!)

Nicole nods to the affirmative.  She's become accustomed to my exclamations of surprise.

This was what I have come to call "Life Lessons".  I recall being fanatical about virtual memory.  I set it, tweaked it, then tweaked it again.

But somewhere RAM became plentiful, and I rejoiced.  Then 64bit operating systems came out, and I frolicked in the amount of RAM I had at my disposal.

Then I forgot about virtual memory.  With all that RAM, it surely couldn't make the difference it once did, right?

The answer seems to be..... WRONG!

Needless to say, I let myself make an assumption, and get sloppy! 

What's the moral of the story?  Don't forget the basics.  Even with a screaming processor, boatloads of RAM, and a Video card with enough power to dim the lights in the office, shorting your virtual memory can hobble your system!



Setting Virtual Memory in Windows 7


So how do we set virtual memory?  Here's a quick video in Windows 7.  Other operating systems set the virtual memory in a similar way!

4 comments:

  1. Hi Jon,

    You mentioned 1.5x RAM in your post. Would you consider this to be a good 'Rule of Thumb' - or is this only relevant to the computer in question?

    What's the best way to judge how big your page file should be?

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  2. Paul, 1.5x is a good rule of thumb. On my system, the computer coincidentally recommended 1.5x RAM.

    Not sure what other computers would do though!

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  3. How about this? A 6gb machine saddled with WinXP 32 bit, so it can't use all the physical RAM.

    1.5x RAM WinXP can USE or 1.5x Physical Memory?

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    Replies
    1. Ted,

      Bummer about not being able to use all your RAM. That would be the best way to go.

      You should be able to still address 1.5X your physical RAM for virtual memory, but you can't beat physical RAM...

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