I had the same issue in Yosemite as well. Using the wired Apple Mouse (formally known as Mighty Mouse), the scroll speed settings are messed up. On the very first notch (left) the scrolling speed is painfully slow and all the rest of the notches are exactly the same speed... STUPID FAST. One tiny scroll with the scroll bar and I can go from the top of a web page to the bottom. Does Apple think nobody uses the wired mice anymore? I prefer wired because it's lighter, it glides more easily and it's not as sharp to the touch. Also, with the wireless mouse, it's hard to keep it straight up and down while using it and the sled runners on the bottom is a horrible design. So my question is... is there a fix for this odd scrolling behavior with the Apple WIRED mouse? In Lion/Mountain Lion (haven't tried Mavericks), the scroll speed settings work.