Questions about FCP X and OpenCL
by Rich Hayes on Oct 15, 2012 at 6:13:37 pm
Hello, I'm new to FCP X and have some questions that I hope someone can help me with.
First, my hardware set up is a 3,1 Mac Pro running 10.8.2. The MP originally came with an ATI 2600. Last week I bought an nVidia GTX 470.
Originally, I was running FCP X on the MP with the ATI 2600 even though it is not OpenCL compatible. A dialog box would pop up at launch stating that the graphics wasn't supported but everything would work nonetheless.
Last week, I bought an nVidia GTX 470 because I wanted to try out Davinci Resolve and hoped that FCP X would be faster. So, I replaced the 2600 with the GTX. However, I started having problems. Whenever I would switch between FCP X and Safari I would get full system freezes and would have to do I hard restart.
I could not figure out why the freezes were happening so left the GTX in slot 1 and added the 2600 to slot 2. Monitor is plugged into the 2600. The freezes seem to have stopped. Resolve is happier this way anyway. What is curious to me is that FCP seems to detect that the GTX is present because the dialog box no longer pops up warning that I don't have a OpenCL compatible card even though the monitor is plugged into the 2600.
I guess my main questions are...
1. What does FCP X and Motion use OpenCL for?
2. How is FCP X and Motion seeing that I have an OpenCL compatible card installed even though the monitor is plugged into the 2600?
3. Are FCP X and Motion using the GTX 470 since, apparently, it sees that the card is OpenCL compatible? How can I test this?
Re: Questions about FCP X and OpenCL by Jeff Kirkland on Oct 15, 2012 at 7:03:06 pm
Both FCPX and motion are GPU accelerated and an Open CL capable GPU is their minimum requirement for that. Resolve is also GPU accelerated and has similar but even higher requirements. Resolve prefers you use one card to handle the mundane stuff like displaying the user interface and one card dedicated to just GPU based operations.
The second point is more an OSX thing but yes, FCPX, Resolve, and Motion are asking OSX to supply them with a GPU capable of OpenCL., and that doesn't have to be the one you are currently using to display things on the screen. In fact, that should be the slightly better option as the better GPU doesn't have to split time between the apps and the user interface.
I would think the above may also be a little application dependent. I'm sure there'll be other poorly written or older apps that assume just a single GPU.
You can test the above by taking the new card out and seeing if the GPU warnings come back. You pretty much get what you see on the tin. If the apps have an OpenCL GPU available to use they'll stop asking for one.
As to the computer freezing... try moving the new card to a different slot. For whatever reason, some cards seem to work better depending on the slot they're put in.
I also had some weird freezing and crashing issues when I first upgraded my Mac Pro 1,1 with a new graphics card but they went away when I did a complete reinstall of OSX.