Which area you farm is decided by the area's monster level, not by the item —
the rule is the same for everything, so it lives on the
mechanics page.
NAMED TARGETS
Named monsters that can be farmed deliberately. The list spans all three difficulties;
each monster appears once, at its most rewarding one.
The figure is an estimated average kill count.
Duriel
normal · Lv 22~1 every 502 kills
Andariel
normal · Lv 12~1 every 512 kills
The Summoner
normal · Lv 18~1 every 962 kills
Blood Raven
normal · Lv 10~1 every 1,000 kills
Radament
normal · Lv 16~1 every 1,172 kills
Diablo
normal · Lv 40~1 every 2,008 kills
BASE ITEM DROPS
expected per kill
This counts how often the plain Ring drops. A dropped base still passes
a quality roll before becoming this item.