i got 2 eth thresher insight, 260ed/1cs & 230ed/3cs,which one can make more damage?

depends on ar as well (chance to hit) and rest of gear (+ all skills enhances CS as well)

2nd one will be better in regards to damage.

of course the ar and all skills buff r the same to both,which will cause more damage?

tyvm,plz explain to me how to get this conclusion

Depending on your skill level of your mercenary, he will have 16% more chance to double his damage with the 2nd base vs the 1st base. This includes all physical damage dealt, so that means his default damage will be factored in.

Without knowing x as default mercenary damage, you could do the math yourself.

1st insight: 1.16(x+260ed weapon avg + other phys)
2nd insight 1.32(x+230ed weapon avg + other phys)

thx a lot

insight runeword has a variable +[180-250]% to attack rating. since this differs quite a bit, your merc''s chance to hit will do so as well...
assuming this is equal for both your insight threshers, the dmg output will also depend on the amount of + all skills on your merc, since that will benefit the CS oskill. the higher your CS level, the less bonus you get from more points here.
since the merc should get mainly multiplicative boni to his dmg, those will cancel and can get ignored
the dmg formula is then
dmg=(1+crit)*(1+ed)*base dmg*(1+mult)
base dmg and mult are the same, so the important term is
(1+crit)*(1+ed), the higher the better

0 all skills: 4.176 vs 4.356, second wins
1 all skills: 4.5 vs 4.554, second wins
2 all skills: 4.752 vs 4.686, first wins
3 all skills: 4.968 vs 4.818, first wins
4 all skills: 5.112 vs 4.917, first wins

so as soon as you use gear with at least +2 all skills (like either andariels or coh or enigma), your merc will do more dmg using your first option (high ed, low CS). as long as you use at max +1 all skills, your merc is stronger with your second option (low ed, high CS)

i get it now,thank u so much