Radeon HD 5xxx series inflates cursor in Windows 7
 

Sometimes, out of the blue, the Windows mouse cursor doubles in size. No, we're not making this up: we actually observed the problem first-hand on an XFX Radeon HD 5770.

A visit to AMD's Game forums tells us the issue affects Radeon HD 5800-series cards, as well, and the new Catalyst 9.10 drivers don't seem to help. Users who complain typically run Windows 7, and some talk of multi-monitor setups, but they look to have little else in common—the problem seems to apply to certain DX11 Radeons running on both Intel and AMD platforms.

http://techreport.com/discussions.x/17819