https://d4builds.gg/builds/985f733b-817c-4fb9-8c51-c2c1dd4faea0/that's my setup.
Deffinetly the fastest build and class in the entire game.
7th paragon board (enchantment master) is changeable, and glyph in it is changeable. You can use whatever you want as 7th board.
when running NM52-56 with bosses - i always wear in inventory:
2hand staff with control aspect!
amulet (cdr. mcr. 2def) with accelerating aspect!
all stats on items are listed in their priority.
Amulet has only 3 stats. coz its insane to find 4/4 amulet.
No FlameFeeder and No Firebolt enchantments. (because you already overkill)
No Glass Canon. (because if you are running t52-56 you already overkill everything)
this is the fastest sorc build.
all ice shards builds that are presented on youtube or maxroll - are with FireBolt+GlassCanon. its ok if you planning to push t70+
if you are just farming 40-55 tiers - GLASS CANON + FIREBOLT are too much of overkill.
Also - never put Elementalist aspect on Amulet (like all the other guys tell). the best choices for amulet are:
Accelerating
Bounding Conduit