should i uninstall old amd driver before installing new one?

Solution
Typically, yes, it is fine to leave the older AMD drivers in place when you install newer drivers. I do this all of the time and have had zero issues for several years.

spdragoo

Splendid
Ambassador
Yes, you should be fine with installing the new drivers, especially if you use the download utility from AMD's website (so that it auto-detects your GPU & the appropriate driver).

The only time you'll want to consider uninstalling old drivers is if you're physically replacing the GPU. And even then, that's only if there's a big gap between the new & old GPUs (i.e. replacing an HD 4850 with an R9 290X). Of course, too much of a hardware gap means you're probably replacing the motherboard and/or CPU anyway, which means a fresh install of Windows (& therefore fresh driver install).