Yeah I'm using the build you mentioned.
I just did another test with everything switched off and it now runs continuously at 1592x896. I wonder how Julian is getting continuous with global draw on??
Here's a quick screengrab:
https://docs.google.com/file/d/0B6HUSFpmHmZEbFlhdmxEZ2RmSVE/edit?usp=sharing
I wonder too.. but it really works for me.
Just checked again:
GD off, 1592x896, recording around 52-53MB/s, skips after about 500 frames.
GD on, 1592x896, recording around 56-57MB/s, keeps running. After 12GB I got bored and stopped, it just keeps going.
Anyway, the development of the 50D is still early. The fact that it can run like this (and even better for other users with faster cards than my Sandisk 90GB/s) proves that there are good things to come

IMO it already works like a charm, even with all the bugs and errors in the code.
Your screengrab doesn't work, it's not public.