Troubleshooting Ableton Live 9 Suite

Example of audio dropouts in Ableton Live 9 Suite: Example of dropouts in Ableton 9 Suite by September Audio

The audio dropouts I get in Ableton Live 9 Suite have turned out to be quite severe, and the question whether the root cause is to be found in Ableton Live 9, in my soundcard driver or elsewhere on my computer still remains unanswered.

All I can do is systematically go through my setup and one by one removing the things I think might have an effect. This is what I know: Loading the exact same project in Cubase and Live shows that Cubase is perfoming well, while Live is kneeling at very little load.

These are the things I've done so far:
Removed everything Live 8 from my hard drive (just in case…)
Fresh install of Ableton 9 32 bit and Max for Live 6.1 32 bit
Contacted Stenbergs support. They are saying that they have not heard of any conflict between Ableton Live and their driver for my audio interface (Steinberg MR816X).
Reascan Plug-ins (no conflicting plug-in found)
Fresh install of my sound card driver. Cleaned my system hard drive (now 135 GB available of total 320 GB)
Run Repair Disk Permission
Moved Live packs to dedicated sample hard drive (153 GB available of total 500 GB)
Turned off WiFi and checked that there are no background tasks running on my computer (as far as I can see).

Unfortunately the problem remains

I sent a request to the Ableton support team last weekend, but taking into consideration that they've just released a new version of Live I guess they have plenty to do and that I will have to show some patience.