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I manage a fairly powerful workstation, but for some reason the box is very sluggish. Looking at the task manager, I see that almost no memory is free and a lot is used as caches (which IMO should be very similar to being free) -- however the machine is swapping heavily. There are a fair number of large processes open (Lotus Notes, Word, two copies of Visual Studio), but IMO this should not bring down a machine like this one to the point of being unusable (switching task takes several minutes, typing into the active window makes the OS notice that the application is unresponsive, etc.).

Memory Pressure

OS is Win7 64 bit, I have a regular harddisk and a 32 GB SSD for ReadyBoost installed. Is there some obscure setting I may twist to allow the system to use more memory for private mappings rather than disk caches, or am I misreading the numbers? Are there any other things that I can try to make the system perform better?

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migrated from serverfault.com Nov 29 '11 at 16:36

This question came from our site for professional system and network administrators.

    
First, this is off topic. Second, cached pages will be released when live processes need the RAM. It's not your bottleneck. –  MDMarra Nov 29 '11 at 16:19
    
This is a better question for SuperUser. This will get voted to be migrated, no need to take any action on your part. –  mfinni Nov 29 '11 at 16:19
    
No memory should be free - one would hope, windows will try to use what ram it has see serverfault.com/a/75027/3528 for details on windows memory use –  Jim B Nov 29 '11 at 16:24
    
From my understanding, the system should always keep a few "free" (i.e. zeroed) pages so it can map those quickly when a process requests it (so pages can be cleared from another CPU while the requesting process can proceed). –  Simon Richter Nov 29 '11 at 16:56
    
How did you establish that the issue was swapping? How much pagefile is in use? –  David Schwartz Nov 29 '11 at 17:39
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1 Answer

Ughh. Task Manager is a fairly poor tool to measure performance.

For example, when I evaluate how a sports team is doing, do I look at their statistics from one game, or many games?

On top of that, the human brain puts more emphasis, and thus weight, on recent data points, versus maybe more significant but distant data points.

The myth of free memory

From my understanding, the system should always keep a few "free" (i.e. zeroed) pages so it can >map those quickly when a process requests it (so pages can be cleared from another CPU while the >requesting process can proceed).

Zeroing memory pages is a fairly trivial process on today's machine. Disk access, even with top of the line SSDs, dominate the list of sluggish performance factors. There is a reason why Free memory and disk access is correlated in performance, since to an application, they are one and the same thing: secondary storage. While low memory can cause an OS to go to disk, from my observations of perfmon graphs, disk access and network latency (Ughh, I hate our ISP) dominate today's performance concerns.

It is also impossible to read the impact of having Free memory (zeroed pages) on your machine. We have no idea about the peak commits, peak # of page faults, # of pages, etc. I'd caution against jumping to conclusions over what is literally a snapshot.

My suggestions

Take many data points.

If you have local admin access to your machine, fire up perfmon and use the default System Performance Data Set Collector. Have it collect data points every 10 to 15 seconds and run that for several days.

Also take a look at where in your workflow a faster machine would help out. It is possible that a faster machine may do very little. For example, VS2010 can be a memory hog during builds, as it has to load up all the dependencies of your project. I know a few places where they take several old Pentium 4s and "outsource" builds to them.

The "sluggishness" could also be attributed to the application themselves. Not all programs are designed to take advantage of lots of free memory. Some applications are rather aggressive about keeping a low memory profile, but rather keep data on disk since disk space is of little concern.

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