How-To Geek

The Microsoft KB Article with the Silliest Name? This One, Possibly

Most of Microsoft’s knowledge base articles have boring names, and read like the dictionary… incredibly boring. So when we came across this one, we couldn’t help but laugh at the name that’s so out of character.

It’s actually a really useful article as well, explaining processes, memory limits, pagefiles, and even the difference between different counters in Performance Monitor. Here’s a segment of the article:

Memory, Committed Bytes: This is a measure of the demand for virtual memory. It shows how many bytes have been allocated by processes and to which the operating system has committed a RAM page frame or a page slot in the pagefile (or both). As Committed Bytes grows above the available RAM, paging increases, and the amount of the pagefile in use also increases. At some point, paging activity starts to significantly affect perceived performance.

Process, Working Set, _Total: This is a measure of the amount of virtual memory in “active” use. It shows how much RAM is required so that the actively used virtual memory for all processes is in RAM. This is always a multiple of 4,096, which is the page size used in Windows. As demand for virtual memory increases above the available RAM, the operating system adjusts the size of virtual memory in the Working Set for a process to optimize the use of available RAM and to minimize paging.

Paging File, %pagefile in use: This is a measure of how much of the pagefile is actually being used. This is the counter you should use to determine whether the pagefile is an appropriate size. If this counter reaches 100, the pagefile is completely full and operations stop working. Depending on the volatility of your workload, you probably want to set the pagefile large enough so that no more than 50 to 75 percent of it is used. If a large part of the pagefile is in use, having more than one pagefile on different physical disks may improve performance. 

Memory, Pages/Sec: This is one of the most misunderstood measures. A high value for this counter does not necessarily indicatey that your performance bottleneck is a shortage of RAM. The operating system uses the paging system for purposes other than for swapping pages due to memory over-commitment.

Memory, Pages Output/Sec: This shows how many virtual memory pages were written to the pagefile to free RAM page frames for other purposes each second. This is the best counter to monitor if you suspect that paging is your performance bottleneck. Even if the Committed Bytesvalue is greater than the installed RAM, a Pages Output/sec value that is low or zero most of the time indicates that there is not a significant performance problem that is caused by not enough RAM.

Memory, Cache Bytes
Memory, Pool Nonpaged Bytes
Memory, Pool Paged Bytes
Memory, System Code Total Bytes
Memory, System Driver Total Bytes

The sum of these counters is a measure of how much of the 2 GB of the shared part of the 4 GB virtual address space is actually in use. Use these counters to determine whether your system is reaching one of the architectural limits discussed above.

Memory, Available MBytes: This measures how much RAM is available to satisfy demands for virtual memory (either new allocations, or for restoring a page from the pagefile). When RAM is in short supply (for example, Committed Bytes is greater than installed RAM), the operating system tries  to keep a certain fraction of installed RAM available for immediate use by copying virtual memory pages that are not in active use to the pagefile. For this reason, this counter will not reach zero. Therefore, it is not necessarily a good indication of whether your system is short of RAM.

RAM, Virtual Memory, Pagefile and all that stuff [Microsoft KB]

Lowell Heddings, better known online as the How-To Geek, spends all his free time bringing you fresh geekery on a daily basis. You can follow him on if you'd like.

  • Published 07/29/10

Comments (3)

  1. Tom

    Well, I guess that makes more people read it :p

  2. ProstheticHead

    Reminds me of those rancid Windows 7 adds… “I’m a PC and I’m bla.bla..bla…”

  3. Jessie Desolay

    @ Prosthetic Head,
    I thought those were rancid MAC ads.(?) –but come to think of it, TV commercials are automatically muted around here (not a bad thing) so how would I know ?
    That’s not why I’m writing anyway.
    The reason I’m writing, Prosthetic Head, is to ask you: Are you from Ottumwa, Iowa, by any chance?
    Because there is, or was, this GORGEOUS strange-looking swan in one of the lagoons there that –I swear–was named PROSTHETIC HEAD! Not exactly a lyrical name but initially it was just an accurate description– because he had this bizarre kind of trapezoidal brown growth on the top of his head, but only on one side, so he looked like he was wearing half of a very stylishly structured hat
    from some avant-garde haberdashery. for geese. It was better than calling him Menangioma, which is what I was afraid he had. Anyway blah blah blah it turned out it was not a cancerous tumor, or even benign one: he was just this rare (in Iowa anyway), beautiful Chinese Swan Goose (Anser cygnoides if you want to google it) which was such a relief. He came back year after year and he was still there, strutting rakishly around the lagoon last year when I went back to Ottumwa for a visit. Once we figured out he was healthy his name was shortened, to Proust, which suits him much better.

    Anyway thanks, Prosthetic Head! for reminding me of that sweet, exotic bird.

    [ if I could just remember why I clicked over here in the first place...?]

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