Preheat oven to 325 degrees F (165 degrees C). Grease and flour a 9x13 inch baking pan.
In a large bowl, cream together 1 cup sugar and 1/2 cup butter. Beat in sour cream, vanilla, and eggs. Mix in flour, baking powder, baking soda, and salt. Spread 1/2 the batter into the baking pan. Layer with peaches, and top with remaining batter.
In a small bowl, mix 1/4 cup flour, 1/4 cup sugar, pecans, and cinnamon. Cut in cold butter until the mixture resembles coarse crumbs. Sprinkle evenly over the batter.
Bake 45 minutes in the preheated oven, or until a knife inserted in the center comes out clean.