I've been doing some messing around with GeForce Experience trying to record Minecraft gameplay using Shadowplay. While it's not a supported game, I've read that I should be able to use the "Allow desktop capture" to record Minecraft. I have been able to capture my desktop and it shows the running marker 'on' in the corner, but it doesn't capture my Minecraft gameplay...no running marker. Has anyone here recorded Minecraft using Shadowplay?
 
So, I've moved back a couple of GPU drivers to before the 10 series came out, and also to before some newer titles were released. I'm now using v347.88 driver that I read about in these forums as maybe the best driver to use with my 780 Ti. I'm not sure that will help my recording problem and will be testing later. In the process I was thinking about PhysX and if I really needed it. I always do a clean install and have always just selected the main driver with PhysX. If I'm not going to be playing any games that have PhysX enabled, for now, I don't see any reason to download the PhysX driver...right? 

Just for kicks I grabbed the Minecraft demo to find out..ShadowPlay records it fine with "Allow desktop capture" enabled..The Status Indicator shows..Alt + F9 and Alt + F10 recording works fine..Fullscreen and Windowed modes record fine..Driver v372.70..GFE v2.11.4.0..No problems here..Just sayin'.
 
See also the GFE/ShadowPlay FAQ for more info.
 
If you're having problems with ShadowPlay, I suggest trying MSI Afterburner for video capture (and the other features too if you want)..MSI Afterburner video capture also worked fine for me..Open the Settings and go to the Video Capture tab to set it up.
 
Your PhysX question was answered correctly by Scarlet-Tech.