No difference that I know of.
i7 uses triple channel and i5/am2/am3 is dual channel.
Depending on your AMD system you'll be looking at DDR2 or DDR3 memory,
for DDR2 any 6400(800mhz) or 8500 (1066mhz) setup with c4 timings from gskil/geil will be goody, most OCZ as well ( I just don't like golds, platinum and titanium are better ).
DDR3 you should take a look at C8 gskill ripjaws 1600mhz - good value for money.