Hello, I'm currently using Adobe Photoshop CS6 Extended and I am experiencing a performance issue with the brush tool when the GPU option is enabled in the performance preferences.
When the GPU option is disabled I am able to draw lines and marks very quickly with all of the default brush tools available. Even when options such as scattering and dual brush are turned on simultaneously the brush strokes are rendered so quickly on the canvas it feels instantaneous. This is great for me because I use Photoshop and other programs for digital drawing and painting.
However with the GPU disabled I am unable to use functions such as canvas rotation, flick panning, scrubby zoom and so on - features that I find incredibly useful. Also at different zoom levels images become highly pixelated and smooth lines appear very jagged. This obviously makes images very difficult to work with!
As soon as I turn on the GPU option, even at the most basic setting the brush tool renders much slower across the canvas than when it was turned off. However other operations such as zooming, flick panning, saving etc appear to be very fast.
This is quite confusing (and disappointing) as the brush tool is by far the most important tool I use in Photoshop. I spend more time painting marks and drawing lines than anything else. My understanding is that the brush tool should be just as fast to use (if not faster?) when the graphics processor is enabled as when it is disabled.
Here is the setup I am using:
Windows 7 Home Premium (64 bit)
Adobe Photoshop CS6 Extended (64 bit) with latest updates as of 28/11/14
Asus Geforce GTX 560 Direct CU with the latest driver 344.75
16GB available RAM
Intel i7 Quad Core CPU 3.07 GHz
As my GPU does not appear to be working hard at all when Photoshop is running even with advanced settings turned on, I can only guess that this is a problem with the Nvidia driver or Photoshop itself? It seems as if the opengl drawing mode is not communicating properly with the Nvidia driver. That's my guess so far as I'm no tech expert.
I have followed every step of the Photoshop CS6 GPU FAQ multiple times http://helpx.adobe.com/photoshop/kb/photoshop-cs6-gpu-faq.html
But the problem always persists.
I have also followed the advice of others by turning brush spacing up to 10% or higher which does help a little bit but this obviously does not solve the problem!
I would be extremely grateful if anyone could help me to solve this problem - perhaps someone from Adobe can test this on a similar hardware and software setup? I would be very interested to learn what exactly is going on that is causing the slowdown.
I will also notify Nvidia and see if they are aware of the problem.