Go All STR, you get way more value from the Green Gems on your weapons than whatever other alternative you can put on there, like Red or Yellow.
In terms of OPTIMAL dps, the best way to do is to get around 50% chance to crit (which is around 334 crit rate at level 280) and then focus only on pumping up attack/crit attack from that point on. Every critical rate value you get above 50% starts seeing diminished returns in your total return on damage.
Your question is only answerable by personal experience of really high level archers(250+).
What we do know is mob crit resistance scales in this game so even if you go full dex, you still need crit rate equips so the real question is not really just dex or str but do you really need full dex to perma crit on those levels, is the damage suitable enough or going full str plus using good to great crit equips is enough to offset the less than 100% chance to crit that you have a higher DPS than full dex ones because str increases critical attack.
And you might not get the right answer because no one will go full dex or full str in this game.
World boss Dullahan has 101 critical defense, a value higher than any monster I could find on tosbase. Next closest I could find was that ant dungeon boss which had 75.
I was also ignoring all possible shenanigans from ranks 8-10, and dex from equipment, and whatever rogue does.
Me using rogue as an example was just to show that even at 80% + let’s say 10% innate crit rate. I still find crit resistance extremely annoying as it gives a noticeable reduction on your crit procs. Which is why I see 56% against a 0% crit resistance enemy underwhelming once you consider enemy’s crit resist, not to mention, you’re talking about Lv600. A Lv600 enemy should have tons more crit resist.
I don’t know your build, but damn your numbers seem off there.
You say you have 80% crit rate normally? Then you’re skirting the line of wherever the maybe capped crit chance is vs regular monsters. Dullahan is the worst thing to compare to, hes practically a direct counter to crit builds at that level. 428 crit rate is all you need to reach 100% in the formula at level 180. dullahan blocks nearly a quarter of that, assuming that your buffs happen before crit defense!
Heck, I should call you out just for claiming to see numbers in a dullahan fight 
Ok here we go @dmhamilt
TL/DR with only lvl 4 gems and not all that OP gear plus rogue c1 you can critical hit a lot with low dex.
I will share my personal stats for my lvl 200 here:
48 points used into dex
48 points used into con
all the remainig points into STR.
107 critical rate. using the critical chance formula (107 - 101) x 42/by my lvl (200) = 1,26% critical chance against World boss Dullahan. Well thats with no items or gems.
With 4 level 4 gems (2 gems in main hand weapon, 2 in sub weapon) as it shows here : http://toswiki.treeofsaviorgame.com/item/gem
28 (14x2) + 36 (18x2) = 64 (I have only 2 non used level 4 green gems)
Karacha dagger bonus = 11 (using +10 dex neck, still dont have it)
Hair acessory = 12 (already got it)
Total 87.
Now with only Level 4 gems, +11 dex from sub weapon and +12 from hair acessory the critical chance on World boss Dullahan is 19,53%. lol
Now, using sneak hit lvl 5 (+70%), I should crt hit him at least on 70% of time - if I attack him from behind.*
*PS: Looks like Critical resist reduces even the flat +70% bonus from sneak hit, but I never saw a formula to that.
Edit: PS 2: I didnt use any extra points from quests, only the STR bonus from ranks… anyway any extra point will go to STR.
It’s not off. Lv10 Sneak Hit gives me 80% flat crit rate if I hit an enemy from behind. As an Archer, I might have 10% innate crit rate w/o investing in DEX.
My point is, at that high critical rate, from my experience, I’m still getting some white numbers from Dullahan. I get though, Dullahan has very high crit resistance. My point is just that a 2:1 build is only best on paper but as you level and as monster’s level get higher, the needed crit rate to reach “decent” levels will eventually get absurd.
Like for your example. A 2:1 build will have 56% crit chance only considering the Lv600 enemy has no crit resist. Yet we’re talking about Lv600 here so eventually, their crit resist will bloat to unimaginable amounts.
God the ignorance is astounding…Stop posting bullshit, thanks.
Well then mr.smart guy. Goodluck with your 2:1 builds.
The fact that you don’t get my point which is so simple makes me wonder who is more ignorant.
Why even model such low damage numbers, your whole post is absurd. DEX scales better with high damage skills and late game weapons. You don’t even factor in any weapons and choose such pointless small numbers.
I’ll illustrate with a more meaningful model.
2 STR :1 DEX VS Full DEX at 280
Assumptions*
Average damage (FULL DEX)
(2859 * 1.5 + 11) * 0.612 + 2859* 0.388 = 3740.586
Average damage (2STR:1DEX)
(32811.5+433) * 0.2055 + (32810.7945) = 3707.10425
Above assumptions ignores monster defence, missile attribute damage, other equipment, etc. Bottom line is, the better your gear is, the more value you get from your dex. It might well be slightly better to level with a STR build, but since there is no stat reset potion aside from DLC 3 founder’s pack, you should prioritize DEX if you’re looking at the horizon.
I get your reasoning, but they are clearly coming from a simpleton. For instance, you postulate level 600 monsters and predict that they will have astronomical crit resist numbers. Where is the proof that crit resist gets exponentially higher for higher monster levels. Level 280 monsters have crit resist that range from 20+ to 100+.
I just checked the monsters at Earth Tower, saw that they only have 20-100+ crit resistance. I’ll admit I have overseen this and simply assumed that enemy’s crit resistance gets higher as they level.
Being rude is uncalled for though.
For your post on full dex being the best by using an example with a skill that has a considerable amount of fixed damage. I could also say its coming from a simpleton.
There are skills with very huge modifiers in this game where STR can scale better. Having pure STR or pure DEX build is subjective. It depends on the overall class build.
I already said that DEX scales better with high damage weapons and skills. Now you’re saying that i’m a simpleton for not knowing what i just said? What? Mind blown.
You conveniently ignore critical rate from gems and other items on your math and brags about dex. Thats funny.
I already put a disclaimer at the bottom saying that not all variables are factored. If you wanna factor in gems go ahead pluck the numbers in. Learn to read and think for yourself.
I read what you said.
Yet your end conclusion is,
This is really misleading.
I dont want to be rude but… YOU ARE BLIND ? I did that just above.
“TL/DR with only lvl 4 gems and not all that OP gear plus rogue c1 you can critical hit a lot with low dex.”
That post was just a copy and paste from my response to a fletcher build in another thread. DEX is flat out better for that build and is true for many archer builds.
The only people who ask whether they should go str or dex are just lazy ■■■■■ who don’t want to figure out which stat if best for their build, hence they come to the forums asking for generalizations. And so i gave a generalization for the masses of idiots to make their lives simpler.
Oh i skipped your post since you were just looking at crit rate. Which is pointless since crit rate is just a part of average damage. I dont feel like discussing with mypoic people who only care about how many times yellow numbers pop up.
Fine. I’ll let this go since I can totally relate.
Again though, there’s no need to be rude.