Below are the difference between 7.1 and 8.1 of infa..
1) powercenter connect for sap netweaver bw option
2) sql transformation is added
3) service oriented architecture
4) grid concept is additional feature
5) random file name can genaratation in target
6) command line programms: infacmd and infasetup new commands were added.
7) java transformation is added feature
8)concurrent cache creation and faster index building are additional feature in lookup
9) caches or automatic u dont need to allocate at transformation level
10) push down optimization techniques,some
11) we can append data into the flat file target.
12)Dynamic file names we can generate in informatica 8
13)flat file names we can populate to target while processing through list file .
14)For Falt files header and footer we can populate using advanced options in 8 at session level.
15) GRID option at session level
Effective in version 8.0, you create and configure a grid in the Administration Console. You configure a grid to run on multiple nodes, and you configure one Integration Service to run on the grid. The Integration Service runs processes on the nodes in the grid to distribute workflows and sessions. In addition to running a workflow on a grid, you can now run a session on a grid. When you run a session or workflow on a grid, one service process runs on each available node in the grid.