FireFox 3 and svchost.exe at 100% CPU

User Help for Mozilla Firefox

Post Posted July 19th, 2008, 3:56 pm

First off, I absolutely love FF3 (FireFox3).

However, there has been one issue that has plagued me with it ever since I upgraded to v3.
It would seem that, at random times, svchost and FireFox3 would suddenly take up 100% of the CPU's time. The wierd thing is that it's not one or the other that takes up 100%, but both of them together. After a couple of seconds pass, sometimes minutes CPU usage would return to normal.
Now, I've done all sorts of checking and fixing, including checking for updates, making sure this svchost isn't a virus/malware, and through the usage of Process explorer, have found that the main service that runs under this svchost (meaning the one that likes to goto 100% shared w/ FF3) is dnscache.exe. Another pattern that I have noticed is, that once they're going @ 100%, my internet hangs. If I try to open another tab, the status bar will say that it's "looking for" the specific site, along with any other tabs that might have been loading as well.

I've had this problem for such a long time now, and it seems like it's becoming so intrusive, that I'm beginning to loose my faith in FF3. I have no idea where to go from here, and just want to be rid of this problem.


Oh, and if it helps any, the svchost that hangs has the owner "Network Service"

[Edit] Go figure, it just happened when previewing this post....


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Post Posted July 19th, 2008, 6:17 pm

What is the program 'dnscache.exe' from? ( Don't think i've seen it in XP ).

( The internet not working while they are not responding makes sense, first you will have almost no CPU and second dnscache probably is preventing the response from the dns if its hanging too. )

( I have seen svchost.exe have cpu spikes, but they should only last a few seconds. )


Post Posted July 19th, 2008, 7:25 pm

Er, sorry, it's not dnscache.exe. The proper file name is dnsrslvl.dll
The only information that I know about it is that it has something to so with resolving dns names into addresses.

Other than that, Process Explorer doesn't list any other services that use that specific svchost instance.


Post Posted August 18th, 2008, 3:08 pm

1. Visit the Microsoft site and download the patch for KB927891. Both x86 and x64 versions of the knowledge base patch are available.

2. Visit the Microsoft site and download the Windows Update Agent version 3.0 for your computer. Both versions for x86 and x64 are available. (WindowsUpdateAgent30-x86.exe or WindowsUpdateAgent30-x64.exe)

3. Apply the patch for the KB927891 to your machine.

4. Reboot.

5. Install the Windows Update Agent version 3.0.

6. Reboot.

7. Your problems should be resolved and your computer will perform normally!

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