I've seen this reported before.
It has to do with having both GPUs of a dual setup enabled. I believe the workaround was to disable the low power GPU in the operating system so that Photoshop would only use the high powered GPU.
you've been very helpful,
excuse me if climb on you but where can i find the option about the gpu of OS, on the system preferences window?
i try to find but nothin founded
With a dual-GPU setup, one will usually disable, say the Intel GPU in the system's BIOS.
If one has such a setup on a desktop, in lieu of a laptop, there might be jumpers, or DIP switches on the MoBo, but I would still check the BIOS first.
If you are not comfortable with BIOS, you may be able to disable the lower-powered (unused) GPU from within Device Manager on your computer. The real fix is to disable it via BIOS though if it is an option.
I honestly don't know how, specifically. I don't have such a system. I'm only passing along what I've read here.
Might be best to do a web search with make of computer and ask something like "disable second video card".
hi there, sorry for the delay i think you all were with bated breath, anyway...great!
the solution: Go to System Preferences > Energy Saver > Power Adapter then select "Higher Performance". That force OS X to use the faster GPU all the time.
thanks all guys!