Hi
I also have an issue with my AIO - It runs as crap as the generic drivers
I Have a decent system like you , 99% passmark test and 8.7 windows experience
I use win 8 as I know how to tweek it to run well
I have a super PC for games but it doesn’t seem to translate into DAW production
I just did a new SSD clean install of Win 8 with basic cubase and nothing else. No internet etc.
And even with no project loaded the Performance meter is showing signal at 256 buffer on my AIO
And I get the odd spike about 2 per minute
Removed all hardware possible, disabled loads in Device manager , performance tweeks ,bios tweeks etc. etc
I have tried literally everything, all pcie slots, power settings, the Visual C suggested on here
NOTHING WORKED 
So how did you get on - I am thinking just to get another card - this has been a pain in my butt for nearly 1 year and now I cant even work on it since my projects are large and ready to mixdown
Cheers
Stu