What happens if one installs Catalyst without uninstalling the old version ?

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http://forums.anandtech.com – Just like the title says. I installed windows 8, let it update to windows 8.1 Then I installed Catalyst 14.4 for my HD 7870 without uninstalling the old version (windows put catalyst version 13.something automatically so I forgot about it). The installation went smoothly but I haven't actually played any games. Should I went through the whole thing against i.e. uninstall 14.4 and install it again ? What are your experience when doing this ? (Hardware)