I have recently installed Ubuntu 13.04 having previously run 12.04. I had found that Firefox would consume excessive CPU resources, but even without running Firefox, the system is incredibly sluggish. I suspect the problem is the combination of 13.04 with NVIDIA, but I cannot confirm.
Having noticed the problem mainly when running Firefox, I posted the question to Mozilla support. It was suggested that I turn off the option in Firefox to use hardware accelleration. Having done this, my system is now usable, but overall performance still leaves something to be desired. Still sluggish, but at least I can switch to another Firefox tab in under 5 seconds (which might take up to 10 seconds, with the screen graying out as if not responding, before I changed the aforementioned option).
I am running version 304.88 of the NVIDIA driver, but have tried every one of the four available driver options.
Ubuntu 13.04 has a few featured that I wanted, but I am considering dropping back to 12.04 as the performance of that version was excellent. I really hate to say this about Ubuntu, but since installing 13.04, it's worse than using Windows.
I have see a few online references to people having such problems with 13.04, but from most of what I have read, it seems that 13.04 is supposed to perform better than previous versions. From prior experience, I have found that the Ubuntu+NVIDIA combination has always been a headache, but I have always gotten it to work very well, until now.
Are there any sources that state how best to configure this particular graphics card with Ubuntu 13.04? Or am I barking up the wrong tree? Any suggestions will be appreciated. I have expended a lot of time on this, and I really need to return to productivity.
I will also note that I am currently running "top" in a terminal window and, just by typing this post, Firefox is running from 50% to 85% CPU usage. Seems to be a bit high to me, but much better than the 110% or more it would use before disabling the hardware accelleration option.