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Why does Firefox's Task Manager differ so much from Process Explorer in how much memory its using?

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  • 1 has this problem
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  • Last reply by moz2u

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Sometimes my updated Win7 Firefox stalls when loading websites. Of course sometimes its the website's fault. Crosschecking with Process Explorer I noticed something odd. In Firefox the Task Manager didn't show any great memory use but in Process Explorer it showed huge memory use. How can there be such a discrepancy and which one is accurate? I'd trust Process Explorer because the computer slowed down a lot when it showed a lot of memory use and as soon as I had closed a few tabs (not making much of a difference in Firefox's Task Manager but a huge difference in Process Explorer) all was fine. I'm using a i5 CPU with 16gb DDR3 ram. In almost every aspect the system is just fine, rarely showing its age. But I'm diligent in watching for programs running in the background, always checking Services.msc and MSCONFIG for newly installed programs that have elected to run all the time in the background for no sensible reason.

Sometimes my updated Win7 Firefox stalls when loading websites. Of course sometimes its the website's fault. Crosschecking with Process Explorer I noticed something odd. In Firefox the Task Manager didn't show any great memory use but in Process Explorer it showed huge memory use. How can there be such a discrepancy and which one is accurate? I'd trust Process Explorer because the computer slowed down a lot when it showed a lot of memory use and as soon as I had closed a few tabs (not making much of a difference in Firefox's Task Manager but a huge difference in Process Explorer) all was fine. I'm using a i5 CPU with 16gb DDR3 ram. In almost every aspect the system is just fine, rarely showing its age. But I'm diligent in watching for programs running in the background, always checking Services.msc and MSCONFIG for newly installed programs that have elected to run all the time in the background for no sensible reason.

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The Firefox Task Manager (about:performance) only shows the memory usage of tabs and extensions, for a better understanding you can use the about:memory page that lists all processes.

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Great to know. I'll definitely cross check that as well next time it acts up. Of course as soon as I posted this all settled down to normal. Such is life.