Mac Forums

So heres the question
I have a Mac Mini 1.66Ghz with tiger and iife 06'. I always seen it as a pretty fast computer. It doesnt seem slow at all but i was looking at the specs and found out that my mac has a Core Duo and the newer 1.83 version has core 2 duo and the website even says its 39X faster than the previous one. Is there really that big of a difference btwn them?
So i have around 300 dollars to spned at Apple and i was planning on just buying Leopard and iLife 08' for my Mac but do you think it would be more worth it to sell my mac on ebay and combine that money with the 300 dollars and buy the new 1.83 Ghz version? but I dont have the box or anything. I just have the remote adaptor and mac which is pretty much all it cam with but do you think it would sell good without the box?