None of the two apps showed me the temps for the graphics card...
So, Dr. Bresink said that SMC in MP does not communicate with GPU sensors at all. OS X graphics drivers also do not provide sensor reading (Windows ones do), so monitoring software can't access it in any way.
So, if you want to see your GPU temp in OS X, you got to bug Apple to add sensor support to graphics drivers...
Does it change itself under load? I'm asking, because Unigine Heaven 4.0 has GPU monitoring as well, but it always shows 39-42C, like on your screenshot, no matter what card I have installed.
42C would be pretty low for Q4000, usually it idles at ~55C and goes up to 90C under load (CUDA).
idle temp -> ~52C
gpu load under BF4 for Mac -> 53C
Can't be right? When in Windows temps go up till ~80C when card is stressed with i.e. Tomb Raider 2013.