[I started my own thread since I hijacked the other, and that's not nice! ]
 
I just noticed something tonight with my particular crackling issue.  I noticed that when moving the mouse around, particularly when moving MIDI notes in the PRV, that it only crackles the audio, (like in my previously posted video), when the MultiDock, i.e. the container for the PRV and other tabs, is maximized to full screen!!!  It doesn't matter if it's maximized to monitor #1 or monitor #2.  It acts the same. However, if the MultiDock is docked, then it's all good. Heck, I can even open the SYSEX window with absolutely no crackles!
 
Pardon my language, but this is a serious, WTF!?!?  How in the heck do I correct for this!? I can post a video if necessary to further describe this ailment.

So I'm doing a little tinkering and investigating with LatencyMon.exe, and the worst offenders in the Drivers list when I get the full-screen snap, crackle and pops are: dxgkrnl.sys, WDF1000.sys, nlddmkm.sys, Wdf01000.sys, MAudioMIDISPORT.sys, HDAudBus.sys and SaffireAudio.sys.
 
The two that are strange are MAudioMIDISPORT.sys, HDAudBus.sys. I think the HDAudBus.sys is part of the Realtek onboard sound drivers. However, in Device Manager, I have Realtek HD Audio disabled. And the MAudioMIDISPORT.sys driver is totally perplexing because the MIDISport isn't an audio device!
 
EDIT: Well, experimenting with a project WITHOUT using the MIDI interface (i.e. VST synth only) keeps this driver off the top of the chart. Whew.

At this point in time, I don't expect anyone to be able to help me... but if so, then that would be awesome!  This thread is more for a log of my troubleshooting actions in the attempt to rid my system of my persistent and annoying glitchy audio. "I've had enough of it! Time to act!"

So I did two tweaks tonight: removed the TI chipset PCIe Firewire card and replaced my Nvidia GeForce GTX670 graphics card with my old ATI HD 4870 card.
 
Tests with a maximized MultiDock window and moving MIDI clips around did NOT result in glitchy audio!  Running LatencyMon in the background when audio is playing and moving MIDI notes around revealed NO driver latencies above 2.0ms like before. The highest offender this time around is ntoskrnl.exe with a tiny latency of 0.248ms. Our friend dxgkrnl.sys remains on the list, but it's in sixth place with a booming (sarcasm) 0.066ms latency.
 
I will test again by reinserting the Nvidia card but leaving the PCIe Firewire card removed. I removed the Firewire card in the first place because it did not improve anything anyway after I installed it.
 
So could it be the Nvidia card causing the issue?  If so, then that completely and utterly blows!!!
 
Anyone else experience trouble with Nvidia cards?

Please get the latest mix control software from Focusrite. Please note if you have installed the latest version you should not need to use the legacy firewire driver any more.
 
Please install the latest nvidea driver from their website, when you install it make sure it's a clean install, do a custom install and ONLY install the driver and not the other gunk that goes with it.
 
Also go to the Intel autoupdate driver site and maybe think about updating your PC BIOS.
Finally run Windows update...
 
Ta

Thank you for the reponse, CakeAlexS. I will respond to your suggestions:
 

CakeAlexS
Please get the latest mix control software from Focusrite. Please note if you have installed the latest version you should not need to use the legacy firewire driver any more.

 
Installed the latest MixControl (version 3.3) this morning BEFORE removing all the hardware as stated in the last post. It even updated the Saffire's firmware, but the trouble still remained. Also, I haven't used the legacy driver since version 2.4 or 3.0?
 

CakeAlexS
Please install the latest nvidea driver from their website, when you install it make sure it's a clean install, do a custom install and ONLY install the driver and not the other gunk that goes with it.

 
I also did this before yanking out the hardware.  I performed a clean install.  No improvement.
 

CakeAlexS
Also go to the Intel autoupdate driver site and maybe think about updating your PC BIOS.

 
BIOS was updated to the latest and perhaps greatest quite some time ago.  ASUS' last update was back in November 2010. (v2209).
 

CakeAlexS
Finally run Windows update.

 
Stupid Windows update reports needing a new Nvidia driver even though a) an ATI card is currently installed, and b) just before the hardware swap-out, the latest Nvidia drivers were downloaded from Nvidia's website and loaded (with a clean install no less).

Yeah I get that unnecessary nVidea update via Windows update, I've hidden that now...
What Windows firewire driver are you using in device manager?
If you are using legacy then put it back to the default...

That's all I can think of other than juggling the slots or cards around which you have probably already done..
 
Cheers...

CakeAlexS
Yeah I get that unnecessary nVidea update via Windows update, I've hidden that now...
What Windows firewire driver are you using in device manager?
If you are using legacy then put it back to the default...

That's all I can think of other than juggling the slots or cards around which you have probably already done..

Yep, that sounds like a good idea! Even though you crossed it out, I am using the LSI 1394 OHCI Compliant Host Controller driver.
 
Unfortunately, my mobo only has one graphics card slot, but further tests are in order!
 
Thanks again, for the responses!

Another thing, check Microsoft's site for any USB hotfixes (I assume your mouse is USB), disable your virus scanner, and disable your network card driver to see if this makes a difference... And disable any ports in your BIOS that you are not using, maybe try another mouse.
 
Sort of scraping the barrel a bit just suggestions - cheers...

Oh and disable Intel speedstep in BIOS (Speedstep is evil!)... ta