Hi people This is how it worked for me, and it will probably work for you! First I had HD 5670 wich did not met the minimum VRAM requirements (only 512MB) so I bought HD 6750 BUT it did not work I had an old driver and in the info in Lr there was "GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS" so I thought that the texture units are not enough. For the HD 6750 they are 36 according to GPU BOSS. So I thought that even my "new" card is no good even with the newest drivers installed BUT thanks fivero's post in this tread I've decidet to do a clean install to an older driver. So I've uninstalled the drivers with this Display Driver Uninstaller Download version 15.0.0.1 and then installed drivers version 14.4 from here http://support.amd.com/en-us/download/desktop/previous/detail?os=Windows%207%20-%2064&rev=14.4 AAAAAND it WORKS!!! The graduated filter for example is sooo smooth!!! Maybe enabling tripple buffer will also help but mine is currently disabled. And for those for which this method does not work maybe there are not enough TEXTURE UNITS although I think Lr requires 48 but mine are 36. Hope this helps And many thanks to fivero!! P.S. Graduated filter is much faster... however brush is veeery slow.
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