Low GPU usage while playing The Witcher: Enhanced Edition with GTX 580 3GB

I am having a Gaming desktop at my home with GTX 580. The desktop was set idle from long time, lets say about 4 months. Couple of days ago i started playing The Witcher Enhanced Edition. After playing for these 2 to 3 days i noticed that need my GPU usage is now reduced very much. It is just around 30% of the total GPU. i checked my settings, its all fine, running on the maximum settings than what is the cause of such a low GPU usage ? My FPS is about 50 to 55 on the vsync, still I can see the game is lagging and shuttering . I done few tweaking on the Nvidia Control Panel but that even do not fixed the issue , I have done everything that possible like uninstalling and reinstalling the driver but still the same problem. Is there any specific reasong for my problems ? Also let me know how can i fix all these things. Thanks.

Since you have mentioned that you have tried uninstalling and reinstalling the driver and it has not helped I just wanted to ask if you have tried updating to the latest driver available?? If not then try out the same and check if you are getting any help from it. Just make sure that you are making a clean installation of the latest driver. You can use driver sweeper for uninstalling the old driver completely or some other third party driver uninstaller that you prefer. Let me know if the issue exists after updating the driver for further help.

I have checked about the same and have found one mentioning that he was facing the same issue but was able to fix it out by performing the below steps:
First uninstall the game along with all the mods that you might have installed.

• Now uninstall the old driver using driver sweeper.
• Once you are sure that you have removed the old driver completely then you can try installing Driver version 295.51 or above.
• After installing the latest driver,install the game from scratch and you are done!!

Just try it out and post back if the issue gets solved. If not then feel free to ask, I will try to help you out with other possible solutions.

Yes updating to Driver version 295.51 or 280.26 should help you out. If that’s not helping then you can try overclocking your GTX 580 3GB using MSI afterburner and keep an eye on temperatures and usage. If at all you are not getting any help from these solutions then post your system specification, there are possibilities where you might have to overclock your CPU. Just post it here so that I can have a better idea of your case and will try to help you with an effective and possible solution further.