I've done my research and searched through the net for a solution. This is what I have:
I am using a Windows 8 laptop with a NVIDIA GeForce 9600M GT video card. Whenever I try to export a video on Adobe Premiere Pro CS6, it would take 8+ hours to complete. This is pretty horrible to work with if you're trying to come up with a video daily.
So I read up on Mercury Playback Engine and found that it could considerably speed up the process. The problem is that only a select number of video cards are compatible by default with this engine, and the GeForce 9600M GT is not included in the list. So I found out that there is a way to bypass this by editing a TXT file and editing the settings on my NVIDIA Control Panel.
So I located cuda_supported_cards.txt in the directory C:\Program Files\Adobe\Adobe Premiere Pro CS6 and edited the file to include GeForce 9600M GT. I saved.
Next, I opened up the NVIDIA Control Panel, went to "Manage 3D settings," added Adobe Premiere Pro CS6 in the Program Settings tab, and set the Multi-display/mixed-GPU acceleration option to "Compatibility performance mode." I saved.
So I opened up Premiere Pro and checked the Project Settings. And what do I get? The Mercury Playback option is still grayed out, indicating I didn't do something right.
So I made sure to update my graphics driver and NVIDIA CUDA. For the graphics driver, I had no problem. For the NVIDIA CUDA, it couldn't install certain features because it said I didn't have Microsoft Visual Studio. However, I actually do have Visual Studio installed on this computer, which is strange. Regardless, I skipped those additional features and updated CUDA.
I opened Premiere Pro again. Mercury option grayed out. I don't know what I'm doing wrong. I know there are people out there who managed to get this to work for the NVIDIA GeForce 9600M GT, so I'm not sure what I'm missing.