Did it in my usual 14+ hours. The trick is to not stop much - I stopped four times, to gas up the Jeep.
Man, the traffic on I-35 stinks. All along the way - Georgia, Alabama, Mississippi, Louisiana, and Texas until Waco - drivers were courteous to a fault. On I-35, not so much. Or at all.
Driving ProTip: if the speed limit sign says "70", then going 65 in the left hand lane on a two lane highway is considered bad form, mkay?