opteron = athlon (for the most part)
all opterons have 1mb L2 cache
165=1.8ghz duel core
170=2.0ghz duel core
175=2.2ghz duel core
the biggest advantage to the opterons is the ablility to overclock to the extreme.
the 165 oc's to 2.7ghz, 170 oc's to 2.78ghz, and i don't know what the 175 does.
144=1.8ghz single core
146=2.0ghz single core
148=2.2ghz single core
these also can way overclock. see "cougar" for his overclock, he has one of the single core processors up to 2.9ghz!
he has a 148 overclocked to 2.9ghz
if you go to www.chiefvalue.comhttp://www.chiefvalue.com/app/...x.asp?linkid=1&store=7
you can check out all the processors there and compare them.