That's likely voters though, among registered voters it's only:
46-38 Romney
And, it's an Internet poll.
What's even more significant about Romney's 20 pt lead is the fact that McCain only carried Texas by 11 points in 2008. D/R/I of sample is 31/33/28 (R+2). The D/R/I in Texas in '08 was 33/34/33 (R+1). The partisan sample seems fair, if not slightly overly favorable to Dems.
http://s3.amazonaws.com/static.texastribune.org/media/documents/UT-TT-201205-Survey-Day1.pdf
That sample is of RV though. The release does not says what the LV sample is (probably much more Republican if the lead jumps from 8 to 20 points.
So, Obama does actually 3 points better than in 2008 with almost the same sample.