Open a terminal and type in this command:
You'll see entries like these:
This is a "hybrid" laptop with both Intel and ATI graphics.
00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)
01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Whistler [Radeon HD 6730M/6770M/7690M XT]
If you have an ATI adapter, then run the Additional Drivers application in Ubuntu. It will check to see if the proprietary driver is available for your adapter and offer to download and install the driver if you choose.