This is the standard line that you will here regarding those mobility drivers.
Please be advised that AMD offers a reference driver (as-is, limited support) for Mobility Radeon cards because laptop manufacturers will often optimize the laptop by adjusting certain capabilities or specifications of a graphics card to make sure that the entire laptop is running efficiently. As such, our reference drivers may not be compatible with your system. You may see software issues or driver instability issues when using our graphics driver for you laptop.
I would suggest that you goto your laptop manufacture website and download the latest graphics driver from Dell. There driver is specifically modified for your laptop make and model.
So you need to bug Dell or give Leshcat site a view. I don't have a laptop, but my friends get there drivers from the site. This instead of waiting on Dell/HP/ or any other vendor to update driver suite.
AMD A10-5800K, XFX 7850 Ultra OC Edition 975MHz, 16GB RAM, Win 8.1 Pro 64 bit, MSI 7778 motherboard, 500W PSU, HP P7-1235, CCC 13.12 WHQL