Which AMD Graphics card should I install the driver for on Ubuntu 18.04?

I have two AMD Graphics Cards on my system.

I am quite sure that the Radeon HD 7640G works better than Radeon HD 7500M/7600M Series.

I would just like to use only the 7640G and install proprietary driver from AMD site for the same.

A screenshot to about my System Info has also been provided below.

Any suggestions are most welcome.

Thank You

lspci -nn | grep -E 'VGA|Display'

00:01.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Trinity [Radeon HD 7640G] [1002:9903]

01:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Thames [Radeon HD 7500M/7600M Series] [1002:6840]

System Information Screenshot Link