cpu update for my mac

[jyoungsty]

hi.. I have a mac pro(previous original model)-
2 x 2.66 GHz dual xeon processors, 5gb of ram.

Can I upgrade the processor to 2x quad processors?
If yes, Which intel chips(2.66 GHz quad or above)are right for
my mac(motherboard)?
-I checked at some of sites such as newegg.com etc, there were a lots of Xeon processors.
I couldn't know which one was right for me.

Is this valuable for its price?-
(I am asking for its overall performance versus the price, no matter what I do with it.
and my updating starts from 2x 2.66 GHz dual processors, not starting from nothing.
It means, for example, I update it to 2X 2.xx GHz quad with the payment of $500 or up
then if I get just x1.3 faster performance than the current cpu, it is invaluable for me.)

thanks.

[harryb2448]

Do not think this is possible. Apple Discsussions recommends selling what you have and buying an Intel machine. here is the link:-

http://discussions.apple.com/thread....sageID=7839533