Fresh Windows 7 install, Internet connection causing SYS Interrupt to jump to 40% of CPU

I installed Win 7 and then went back and re-installed all of the drivers. I then went into the Device manager and updated the drivers via windows and the internet. Yet everytime I enable the connection to the internet my CPU usage jumps to 100% and 40-60 percent of that is because of the System Interrupts. Any help would be great. Thanks


Microsoft MVP
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Try process of elimination.

You seem to have identified drivers as a likely cause. I'd try a system restore back to before you ran the driver updates then reinstall one by one and look for results. I'd also be more specific in obtaining driver updates. If your pc manufacturer has a site then look there for specific drivers for each device. Alternatively look at the site of the individual device manufacturer. I do not generally allow Windows update to update device drivers - I "hide" all such updates.


Excellent Member
Microsoft Community Contributor
Does the activity continue or just bump? What firewall or anti-virus are you running?

What is your network setup--going through router?

The SYS iunterrupt stays at 100% the whole time. Apparently it is not the ethernet card driver anymore. I connect direclty to a modem. I am using the firewall installed with Win 7. I have found online that my Nvidia driver may bbe the cause, Win 7 keeps telling me that my graphics card does not support DirectX9, could this be my problem causer? I will restore and reload the drivers one by one avoiding letting Microsoft set the drivers. Thanks for your help to both of you.


Excellent Member
Microsoft Community Contributor
So now the problem is not caused by an internet connection?

What video card do you have?

Does your system use Nvidia chipset drivers as well as video?

Which process exactly is it that is taking the processor time, or where are you seeing this? A snipping tool picture attached might help.

Do you see anything in the Event Viewer that might indicate the actual problem?

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I replaced the old NVidia card with a Nvidia 6200 which is compatible with Win7. I went to Nvidia and downloaded their driver, did the install and still no change. Still 100% CPU. It appears as the System Interrupt is using 40-60% as soon as the computer comes online from logging in. I am viewing that on the resources manager inside the task manager tab. i don;t know what a snippet tool picture is, how would i do this?. Also what and where is an event viewer? Thanks for the help

Does the modem show data traffic or is the connection silent while it's 100%?


Excellent Member
Microsoft Community Contributor
Once again, does Event Viewer show any errors that might help. If you do not know how to start Event Viewer, type eventvwr.msc in the Start Menu search box.

You might also open the Device Manager. If you select view, resources by type, you can see a list of the items that might be using it. I do not really know of a way to tie the information together, but maybe it will give you an idea of what might be causing the high interrupt traffic. The Network adapter is probably on the list.

Does you mouse ever lock up when moving?

It appears as the System Interrupt is using 40-60% as soon as the computer comes online from logging in
I had this problem solved after I disabled everything except QoS and IPv4 from LAN-properties. Don't know why all of that affect to processor, even event viewer had logged nothing:confused: Maybe seven tried to operate with local network which wasn't there...

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