I picked up the 14.99 upgrade a few weeks back done an upgrade in place and things have not been so well. Normal use of the computer is fine i.e. surfing web, playing mp3s. But I get awful dropouts with sonar, more so audio glitching than anything else. It seems to be good except for not being able to record, mix, edit my music. Can anyone give some insight on this? Would a clean install have been better? I still have my windows 7 image and have of course the windows 8 install dvd. What should I do? I am off tomorrow and I have to take care of this. My interface is a Roland quad-capture using Sonar x2a and the laptop is a HP with an I5 and 8 gig of ram also I use an external drive for recording. 

Do you have Win 8 drivers for your sound card? Also did you make sure all your drivers are Windows 8 compatible?

Yeah I got the update for windows 8 and uninstalled the old and re installed the new. Nothing else external on this machine other than the usb hard drive. 

Drivers I meant lol. I believe they were version 1.51 for the quad capture. 

Are you using ASIO or WDM. I would try different driver types. I found the WASAPI drivers best for me.

Check your power management settings and make sure it's set to High Performance (or go in there and make sure everything's disabled when the laptop is plugged in). If that's not the problem, you can also open windows task manager and look at your CPU usage on the processes tab when no applications are running. If CPU usage is high, look down the column and see what process is causing the problem.

I purchased upgrade licenses for all my Windows machines. ie 3 of them but have resisted installing the upgrades yet.
When my house is finished being built (by Easter I hope) and I can set everything back up then I'll setup a HDD for Win 8 to start looking at what it brings to the table and how best to migrate. all this done outside of any stable running systems so that I'm not caught out on the unknown. maybe my approach will help you too.

@OP
I have win 8 Pro on my Ausu laptop. It only has USB 3.0 ports. Anyway, my new laptop, Win 8 and my new Roland OCtacapture get a long great. I believe the Quad uses the same drivers. I haven't done any heavy recording with it because I still have my main daw with my Ecgo Layla3G.
 
But I have recorded som guitar and vocals-bounced a few softsynths for bass using Kontakt 5 and Scarbee bass. Used Steven Slate Platinum  4.0 drum Sampler for the drums.
 
Everything went well and actually better than my DAW as far as speed-Probably due to the SSD in the laptop.
 
I am about to do the same to my desktop-SSD and Win 8 Pro.
 
My laptop has the Ivy I7 3770 (numbers could be wrong, but close) 16GB ram SSD for OS. Ext drive for samples.

I wonder if I should have done a clean install? I done some searching and didn't find anyone complaining about the quad-capture and windows 8 having trouble. I done that before I upgraded. Honestly I like windows 8 except the fact of getting so many glitches while trying to record. The same machine with windows 7 I could run low latency with a lot of plugins and absolutely zero problems.

BTW I have been using the asio drivers for the quad-capture, Mudgel I think you might have the solution. I should have just gotten the license and waited to install it once a service pack comes out. Where I got this laptop last summer I got the offer to upgrade for 15 dollars and didn't want it to run out.