GPU Acceleration LR Classic 8.4?

1. Previously, GPU was used to accelerate the display with most of the rendering/processing associated with adjustments being left to the CPU. This latest update moves a lot of the rendering/processing associated with adjustments to the GPU.

2. In the past, the GPU on/off did not cause slow downs when 'I' applied local adjustments. However, others had a completely different experience. It would be silly of me or anyone else to suggest that things will now be different, especially when we have no idea why some users had problems to begin with.

3. Assuming the GPU is supported and the hardware / OS meet the requirement set out be Adobe, then the new GPU support should be more beneficial to users of 4k and higher resolution displays, but users of lower resolution displays will see varying degrees of improvement. For me, using a 2560 by 1600 display, the improvements are very obvious. This is on 2013 Mac Pro with what would now be considered a fairly low end GPU. The key is ensuring that 'Full acceleration' is enabled (i.e. use the Custom option rather than Auto).

Note: my guess is that folk who previously had issues with GPU enabled may well find that there is no improvement. There are many reasons for this, and none are within Adobe's gift to address, but that won't stop the complaints. May be we should just leave folk to test for themselves rather than predetermining the issues they might experience.

See if this helps: