Wolverine uses 100 of his brain, just like all people do. Slade's ability is based around a misconception. That being said it is his body movement that his being read not his mind so it doesn't matter how much he is using. She couldn't read him because he moved to fast.
the average Human uses 10% of there brain, dude.... that's been a fact for a while!
THAT being said, it's not his speed that trumped her... it's his ability to predict batgirl BETTER than she could predict him.