I have a little question about my fresh installation of Ubuntu 12.10 on a Dell XPS 15z (Intel i7, 8 Go RAM, Nvidia GeForce something and an SSD (256 Go).
A few months ago, I installed Ubuntu 12.04 and it was perfect, without any lag or something. Great! Then I uninstalled it.
On Monday, I tried Ubuntu 12.10 with a live USB and it was perfect, fast, Unity 3D enabled, no lags... Great! (Except that I had to boot with the acpi=noirq option, as I read ot on the wiki and as I did before with Ubuntu 12.04.)
Then I decided to install it on my computer. No problems, all went perfeclty fine. When Grub appeared, I enabled the acpi=noirq and... blank screen. I know people have already encountered this bug so I won't go further. (With the acpi=off all was fine, but no battery manager.)
I logged in, no problem. And once the desktop open, all become laggy! It became unusable!
Animations very slow, crachs of Compiz very often...
My question is: How is this possible? How Ubuntu can be slower once installed than on a USB device? And how a newer version can be completely slower (and unusable) than the previous version?
How do I turn off compiz ? killall compiz?