HDAudBus.sys I believe is an HDMI video card/chip/driver's audio.  At least with nVidia video cards disabling it's HDMI audio drivers is really necessary.  It may apply here. 
 
You may also want to see if there is a chipset driver for your motherboard to help with the Wdf01000.sys performance.

First off 128 buffer is to low, unless your recording only, stick to 1024 or 2048 it's no big deal for mixing, just work out your latency and add it into the offset and your good to go.

Secondly I know there is a bug that exists at the platinum primary input for multi instruments . I know this because I found it.

You are using a lot of multi instruments, omnisphere kontakt ez drummer.

A way that u can test if this bug is the causing the problems your expierincing is simple.

Go to all the multi instruments and change "ALL" the primary inputs to "NONE" except for the first primary of each multi instance.

So effectively you now only have 1 x "active" primary input for every multi/synth in your project ( the remaining of the multi primary's are changed to none by you ) now test and see if the spike/glitch/pops are gone !

Good luck

I agree with Kontakt a 128 buffer is going to be too low, no matter what kind of computer.

I had exactly the same issue when using my Scarlett 2i2 (1st gen) with Windows 10.
 
AFAIK the 2i2 uses the same USB driver as the Solo.
 
I installed the latest beta driver from here, which fixed everything for me:
 
beta.focusrite.com/releases/focusrite_usb2_drivers/ 

I've just had an email from Focusrite this week to say there is a new driver available this week 4.36.4
Might be worth a try??

paulf707
I've just had an email from Focusrite this week to say there is a new driver available this week 4.36.4
Might be worth a try??

Yes, I just installed the new driver, thank you both.
But that did not solve the problem.
In the meantime I spoke directly with Focusrite support who recommended me to follow the guidelines of this link: https://support.focusrite...-your-PC-for-audio-on- Windows-8
Apparently it has improved a bit.
I will now follow the results.
Thank you all.

The only thing I see is you only ran the test for 45 seconds. You should run it for a lot longer to catch background processes. I use about 1 hour leaving it going while I work. 

I run the same Motherboard, Processor and a Focusrite Scralett 18I8 as you and im fine.
Try removing the HDMI monitor as a test and try a new project without the VST's/Synth's giving you issues.
You really didn't answer the questions I asked in my previous post. But I understand you have a lot going on.
No worry's im just trying to help.
 
Good luck.