I have a Intel i7 2600 processor, 8GB DDR3 RAM, nVidia GTX570 graphics card, and still Ubuntu taking 45-50 seconds to boot and 32-35 seconds to power off, while Windows 7 boots in only 20-25 seconds and shuts down in 10 seconds. Both OS has Automatic Login enabled, and obviously I am dual-booting.
Ubuntu is slow in Pre loading stage too, and doesn't show any boot splash after installing drivers and didn't recognize my nVidia graphics card on jockey GTK, I had to add "x swat" repository and that didn't worked. I installed proprietary drivers through terminal (
nvidia-settings) in order to have 3D acceleration. But it doesn't make any difference on the speed.
I also have a Pentium 4 PC and in that PC, Ubuntu 11.10 is way faster than windows 7 or XP with nvidia graphics card. And Preload (showing splash screen) is good.
Here is my boot script, some words there are in Spanish because my Ubuntu is in Spanish lanuage.
I am not using WUBI, Ubuntu has its own partition, it is 64-bits, and Matlab 2011 has very low performance compared to Windows version.