Comment 35 for bug 1069843

Also there is a fix for this, which I am using.

Follow these (assuming you are logged in with "user" account) :

user@hostname#> sudo killall nautilus
user@hostname#> sudo nautilus &

(do add sudo while starting nautilus)

What I figured out was, in my laptop nautilus get started with "user" permissions instead of "root" on startup. This created permission issues, and thus nautilus end up taking so much resources. Running with "root" helped.
These are the comparisons, if it can help to anyone :

While running with "user"
Overall computer load : 2.4
CPU : 110%

While running with "root"
Overall computer load : 0.3
CPU : 5%