Using a MacBook Pro 15/8 MB Ram running OSX 10.9.1 - with Safari launch my fans would run up to 5000 rpm within a few minutes. Closing Safari would bring them down to 2,000 rpm. I first tried repairing permissions, but that did not help. I then removed the Safari cache file as described and all is stable.
This issue seems to be fixed now, probably by some update that I installed since (which was addressing a completely different issue ;-)
If anyone still has to deal with this, I've noticed that if I quit Safari the problem tends to go away. After having started Safari again, everything was running fine for a while and then slowed down again to a crawl.
Windows also is also facing similar issues, for the curious people this is how they are addressing the problem: http://technet.microsoft.com/en-us/library/dd837644(v=ws.10).aspx