I was getting some crackles while recording a guitar part - and it was getting annoying. I haven't noticed it before - but maybe it stood out as the guitar part was a little quiet. DPC showed some funny blips at regular intervals (every second or so).
 
I disabled stuff in device mgr (like they say) and lo and behold - the LAN card was causing it!
 
I don't know when this started - but disabling the LAN card definitely makes it go away. DPC is clear and npo more crackles while recording.
 
I'm just throwing this out there in case it helps anyone else. I don't know what has changed - besides Windows Updates, and I think it updated the LAN driver (Intel 82579V Gigabit Network Connection - on a Asus motherboard). This problem seemed to come out of nowhere though...
 

LAN connections are one of the most common reason for DPC dropouts...I always do sessions with networking disabled.  Thanks for the info...
 

I knew about Wifi - but I've never noticed the problem with a normal LAN card. Oh well, we live and learn...

Sometimes unplugging the network connection w/o disabling it makes DPC worse.

I don't ever do the Windows updates for network cards. Only ever the MOBO manufacturer's drivers. If it wasn't happening before maybe you could use system restore to go back or download your MOBO vendors network drivers and over write what windows update did. I've had success with the latter before.

Well, well - you got me thinking mudgel. It was the "Intel Driver Update Utility" that updated the LAN card driver (I'm glad I remembered that) a few weeks ago. I uninstalled the driver - and re-installed the old one from my Asus motherboard downloads - and all is well again!
 
I just had that feeling "surely this crackling hasn't been happening before - without me noticing"...
 
So the lesson is - watch out for the Intel driver update utility (not Windows Update) updating your Network Card driver...

Glad you got it sorted. That ones bitten me before.