No need to uninstall it.. Just set your texture resolution to a lower setting.
The settings are the same up to 512. It's just that the default install doesn't have 1024. These are really also 512x512. Once you install the hi-res pack, then it actually does something when you bump it up to 1024. Now if you can't HANDLE that performance, then just set it lower (back down to 512, 256, etc) and it's the same thing.