Windows 7: High CPU usage due to system interrupts (Deferred procedure calls and interrupt service routines)

Windows 7, much as I enjoy using it (although the shine has worn off a li'l bit), has a few niggles. One of these, which really annoyed me was the sudden seemingly random spike in CPU usage that, once it occurred, never went away until I rebooted the system. The task manager did not list any application as consuming any significant attention from the CPU. However, the resource monitor (which can be reached from the performance tab in the task manager) provided the answer as I found the innocuous sounding "system interrupts" process consuming a steady 40-45% CPU.

Seeing as to how I had no idea why this was happening, off I went to worship at the altar of the Google Gods. This was not an uncommon problem apparently and after reading a couple of reams of bug reports and plaintive paeans for help, I came to the conclusion that this was going to be one of those inscrutable issues where there was no definite answer and that solutions had varying dependencies on wind direction, solar activity and the size of your Mom's feet.

But, one common undercurrent prevalent in all replies provided by people who sounded qualified (if one went by the plethora of M$ certifications in their 'signatures') was that this was not an M$ fault and that the culprit was almost always a bum driver, usually that of the NIC or sometimes the graphics card. The recommendation was to try and disable the device and once identified, look for an update (or vice versa) or attempt to rollback to an earlier version if possible.

Consequently, the next time old unfaithful decided to spike my CPU usage, off I went to my device manager to see if I could arrive at the problem child through a process of elimination. I disabled everything one by one to no avail. I disabled them in pairs and other permutations and combinations. Still, no luck. Of course, I had already ensured that I had the latest drivers installed.

So, it seemed that this was a bum steer. I continued to wait in the hope for a Windows or driver update while resorting to system restarts in the interim.

One fine day, which happened to be about four days ago, I was once again plagued by a CPU spike. However, while checking to ensure that it was my beloved 'system interrupts' process that was the culprit, I found to my surprise that it was some other process named 'audiodg.exe' which was to blame. Another offering at the Google altar revealed a number of solutions chief amongst which was the following:

1. Right click on the 'volume mixer' icon in the system tray and select 'playback devices'.
2. In the ensuing dialogue, there should be a list of playback devices. Double click on the one selected, i.e., the one with the big green tick beside it.
3. In the resulting 'speaker properties' dialogue, select the enhancements tab and check 'Disable all sound effects' and click OK on all the dialogues to save the updated settings.

For those who did not have any effects selected, it might be worthwhile trying to enable a couple, saving it, and then coming back and disabling the lot once again.

The above should automagically solve the audiodg issue. It did for me. But what it also did was solve my CPU spike issue. I haven't had a single one since then! *fingers crossed* *touch wood* etc.

Apologies for the long-windedness of the post ... I tend to feel ... verbose whenever I read Wodehouse :|