ATI Radeon 9600SE or 8500?

Hi all,
in one of my PCs I still have my glorious 8500, which at the time I bought
it, costed me a lot of money (read: many many days of hard work).
Now I have a chance to swap it (for free) with a 9600SE, that as far as I
understood is the least performing card of the 9600 family. It has a 64bit
data bus, to be more clear.
I'd wish to ask you if you suggest me to do this swap, or to keep my old
8500 instead.

Pro the 9600SE there are a couple of points:

1) memory (128MB against the 64MB of my 8500)
2) modernity (it supports DX9 effects that my 8500 doesn't support)

in favour of keeping my 8500 instead there is:
1) 128bit data bus, against the 64bit of the 9600SE

What about performance? Is there any case where the 8500 is still superior?

I always and almost exclusively use the 1024x768 resolution, for gaming.

What do you advice me to do?

Thanks a lot,
Andrea