By registering with us, you'll be able to discuss, share and private message with other members of our community.

SignUp Now!

Windows 7 System Interrupts And DPCs


Honorable Member
May 29, 2009
I've tracked a problem that only began since a recent clean install of the OS, in which the mouse cursor intermittently becomes erratic. When this does happen, the CPU becomes abnormally active, with spikes to about 30%, with the last 3 cores out of 6 going as high as 75-80%. The Performance Monitor shows that the S. I.s and DPCs are what are causing the activity, but of course doesn't explain why they are so active or what is causing it. Previously, I would move the mouse receiver (Logitech Unifying) to a different USB slot, and and it would calm down for a while, but eventually starts acting the same.

I do not know for certain if the problem is with the mouse, the USB ports in use (USB 3.0), or with something in the OS itself or even some other hardware that is conflicting with it. Any idea of how to pinpoint the problem?
Is it possible to try the mouse in a different system?
Hmm... What about using a different mouse? Is there one on the other pc you could try? If you don't see any issues then you know the other one is at fault.
There is, but it has been giving me fits also...of a different sort. I rather dislike the idea of using it, because the problem that I'm dealing with at the moment only occurs at random intervals, and is unpredictable as to when it will occur. Even if I could duplicate the problem with the other mouse, it might take longer than my nerves could take. That is why I only use it on the other PC, because I do little on it requiring mouse control.

Maybe I'm getting the cart before the horse, but I was hoping to come up with a theory based on the assumption that the mouse itself is not the cause of the problem, because I have a hunch that it's not.
So is the system fully updated driver wise as well as bios? Also are you doing anything in particular when the issue starts?
Trouble shooting can be a long drawn out process of elimination and unfortunately there is no easy or quick way of going about things. (unless you happen on the solution almost straight away). That's why i asked about the mouse so to at least rule it out.
Yes, Everything is up to date, except the BIOS, but couldn't be the problem, because it is the same as when I built this setup, quite some time ago, and this problem never occurred before, so I see no reason to suspect it.

The last couple of times it occurred, I was doing nothing, because I leave the computer on 24/7 and it was doling it when I first awoke. I often have several apps left running also, but I haven't been able to connect the issue to any of them.
Firstly it seems that that particular USB wireless receiver is only compatible with certain mice so make sure you check and confirm that your mouse is on the list of compatible devices.
Secondly it seems that it is a 2.4 Ghz device which is not a very discerning spectrum and includes everything from cordless phones, garage door openers, wireless routers, etc., So maybe you might consider the possibility that you may be experiencing some type of proximity interference issues from neighboring devices.
Not sure what if anything you can actually do about that, but I would probably see what I could do with respect to switching channels on any respective devices that you may have and see if that does anything to alleviate the problem.
I assume you are using a wireless keyboard along with the mouse?

New Batteries an any wireless device going through the same receiver?

Does turning the mouse of then on make any difference?

I like to watch the Task Manager with the CPU column set to show the highest usage at the top. I can then see if something is jumping up during the time the mouse is having problems.

Have you reinstalled the Logitech drivers since the new install? What other drivers for your system did you reinstall, like USB or chipset, etc.?

It's the receiver that came with the mouse, so I'm sure of compatibility. The problem is not due to outside RF interference, because when the problem appears, CPU activity is directly related to whether the mouse is idle or not, and I can control the amount of CPU activity by the amount of cursor movement I cause via the mouse.

As I touched on in my last post, the problem isn't caused by any other device in terms of RF interference. Yes, I did install all of the drivers on this install. I did you the Task Manager, as well as CoreTemp to monitor CPU activity, which is how I figured out what I have so far. No other process seems to be involved, other than the System Interrupt And DPC that I already mentioned.