Had a similar issue on my Dell/Alienware M14xR2 with Centrino 2230 on Windows 8 x64 constantly dropping connection when further than a few feet from the AP. Any bandwidth intensive task seemed to drop the connection, even though signal strength was excellent. In addition, the adapter had to be reset each time via the PROset utility to reconnect.
Issue appears resolved with 15.8 drivers. Throughput is down to 72 mbps from 300 mbps but connection is now rock solid.