what´s the difference between the actual one and the 45nm chip??

I mean, is it like, better in rendering than the actual one?

or is it just because its cheaper? (if it is)

sorry for my english

No real difference just cheaper to produce, and they use slightly less power. Because the production is cheaper companies make more money per unit sold, and because they use less power they run cooler.

oh ok!

:O!
thanksss

What jagenjg said.

Also, the cooler it runs... the less fans there are (also cheaper)

And the less fans... the smaller it can be (slimline)

Yep... all that and a bag of chips.

As a bonus, if your fans get smaller, or at least don't need to move as many CCM (Cubic Centimeters per Minute).  You get quiter fans.  It is a big snowball, and everybody wins when the silicon die shrink.