When I started to use LR CC, it crashed (perpetually frozen) very often; in particular when entering into the developing mode. Also, I have a crash with PS CC, and it told me in a popup window it was because the GPU. So, I disabled the GPU in PS & LR CC and as result no more crashes!!
Then, I ran the Windows 7 (64-bit, SP1) update panel and found out an nVidia update, and other one (KB3048761) related to memory-leak issues when multiple windows are open.
I installed both of them and started to have issues with LR CC temporarily frozen each few second of interaction. I had to switch to another application to go back to LR and have response form it. However, PS and all the other applications I use (Google Chorme, MS Office, etc.) were fine. Then, I de-installed the KB3048761 update, and the life was beautiful again.
I felt it was the moment to test the GPU, and enabled it in both LR and PS CC. LR still got frozen from time to time but not very often as before. However PS is fine all the time! I decided to disable again the GPU in LR CC, but it also gets frozen when I just try to disable the GPU!