HI, when put a new processor in the motherboard, between the cpu and the fan we need to put any paste?

Answer 1

Yes. A paper thing layer applied over the cpu heatshield is all that needed unless you use Artic Silver 5 which is formulated differently and you put a pea-sized drop in middle of heatshield over the core if its a single core but a layer over whole heatshield if a multi-core. A buddy of mine built his computer in a "build it yourself" workshop where the instructor told him he didn't need heatsink grease but after I gave him some it dropped the temp of his cpu 12 degrees.
If the base of the heatsink and the heatshield of the cpu were perfectly flat you wouldn't need it but, unfortunately there aren't.

Answer 2

If you want your processor to fail prematurely, then by all means don't use thermal paste.

As far as thermal paste goes, I like Arctic Ceramique. a drop the size of a pea should be more than enough to create good contact between the processor and the heat sink. This particular paste also seems to transfer heat much more efficiently than even Arctic Silver 5 does.

Answer 3

I would say definitely put paste on about half a small pea in the middle is what I use

Answer 4

putting paste on badly is worse than none at all
most new fans will come pre applied
if you are going to do it, dont put on a lot, its there to ONLY take up air gaps

Answer 5

I would put thermal paste on it just to be safe so it won't overheat

Answer 6

Yes. Without it you risk overheating.

One possibility:
http://www.maplin.co.uk/Search.aspx?criteria=thermal%20paste&source=15&menu=-3&WorldSearch=Y&SD=Y

Answer 7

No paste is required. The metal touching metal transfers heat better so it can be dissipated.

Manufacturers use paste to help keep the fan in place while shipping.

Answer 8

yes
put paste...