I had zero problems with my Izotope apps.  I have Ozone 5 and 6, and Nectar elements.   They were all on iLok when I switched to my new i7 6700K build (I have since moved them off of the iLok). I have a couple of their free VST's too that work OK.
 
I had to reauthorize Addictive Drums (may have had to reauthorize Guitar Rig 5, don't remember).
 
My X-Touch and MOTU 896Mk3 Hybrid required "Windows" to reinstall the devices but that was only because they were on different ports with the new build.
 
I have Sonar, Studio One 3 and Abelton Lite 9. They all worked OK after the hardware upgrade.
 

I finally got Ozone working. It took awhile with a few steps, but basically rather than install the Music Product Bundle (which puts stuff all over the place) I installed each component one by one so I could specify where to install the VSTs. I also deactivated some Izotope licenses on my iLok and only activated the MP bundle.
 
DDLY and Morphius still won't work, but I can live without them.
 
My project plan really helped! I probably have 10 hours into re-installs but since I had a plan and I prepared ahead of time, it went really well overall. I think I should backup my boot drive before doing anything else... :)

I moved my Izotope stuff off of iLok.  I've had some problems with iLok (not yet on the new build) and the only thing I have left on iLok is POD Farm 2 and a couple of items I don't use.  Sadly, I can't get POD Farm off of iLok or I could do away with it entirely.

I am sort of wishing I had stayed challenge/response with the Izotope products... :/

"I think I should backup my boot drive before doing anything else"
Really
I would have been burning images all along just in case something went sideways.
An ounce of prevention...
Glad it all went well for you!
T

You're scaring me Tom!!! :)
 
Overall, not too difficult for this one. Had the motherboard not needed a Bios update this would have been pretty darn smooth.
 
The back panel USB3 doesn't seem reliable - I might pull that out. Otherwise, I am rocking!
 
Next up is to fire up my big project that caused me to update in the first place and see how it behaves. Been a bit nervous for that but I'm ready.

What is "not reliable" about the USB 3.0 ports?
 
There are documented instances of USB 2.0 devices not working or not working properly on USB 3.0 ports.  MOTU USB 2.0 devices are one that can have dropouts on a USB 3.0 port.  My MOTU 896Mk3 Hybrid is one, there is a long thread on the gearslutz forum with users reporting similar problems with MOTU units.  I have a 3 1/2" floppy drive that is USB 2.0 and won't even attempt to connect to a USB 3.0 port.  I use the floppy drive to load MIDI song files on floppy discs for my wife's Hammond Organ that has a floppy diskette drive.  Neither of the two devices I have will work on a USB 2.0 external hub connected to a USB 3.0 port.  I had to install a PCIe USB 2.0 port card.

It's important to note that prior to Z77 motherboards, literally ALL USB-3 ports were provided via 3rd-party controllers.  USB-3 had not yet been integrated into the Intel chipset.
This is the reason for many compatibility issues with USB-2 devices.
Liken the situation to using a non-TI chipset Firewire controller with a Firewire audio interface.
It opens the door to compatibility issues...

Thanks guys! So I hooked up a 2 port USB 3 back panel and attached it to the header of the motherboard. I had a USB stick (so probably USB 2) in the back, but the drive would periodically disconnect and reconnect. That makes me leary to plug anything important into it...

OK, fired up my big ass project and all plugins loaded! I did have to re-choose my Sonarworks Adams profile, but that was easy. 
 
The project actually runs with buffers set to 256! I was running at 1024 before, and still getting some stuttering at times and had to run at 2048 to make it solid. Moving the buffers up to 512 and it is running rock solid so far!
 
Wow, I am blown away.