Upgrade MB and CPU

I have an Athlon XP 2600 and FIC KT400A mother board, 1GB ram. I was
looking at upgrading to something faster as the Athlon 64's have dropped
in price.
I can get an Athlon 64 3700+ and Gigabyte GA-K8NF9 mother board for $125
I see 2 versions of the Athlon 64 one is Athlon 64 3700+ 90nm Rev E and
the other is Athlon 64 3700+. What is the difference and is it worth
while to upgrade at this time. I have a Radeon 9800 Pro video card and I
dont play games much. 1 GB of DDR ram.

Comments

Thank you