50% cost 440 Resi = dmg reduce for 10%
440 Stamina increase HP pool for 4200 hp with 40% dmg reduce
with each point more resi, loses this value.
a player with 40% base resi and additional 4200 hp survive always longer as a player with 50% resi without 4200 extra hp.
thats the reason why stamina gems > resi gems
Let's look at some scenarios with your numbers(which are wrong to begin with), shall we?
Let's say a priest's health is 14000 at 40% resilience, now i can have 10% more resilience, i.e., 50% resilience, or 18200 health.
First option gives me 14000/0.5=28000 effective health.
Second option gives me 18200/0.6=30333 effective health.
So on the surface it seems that the second option is slightly superior (2k more effective health). but wait, a priest is most likely shielded. and can receive heals. Let's say the shield is 10k and he heals himself for 50k before he dies, now let's check again.
First option gives me (14000+10000+50000)/0.5=148000 effective health.
Second option gives me (18200+10000+50000)/0.6=130333 effective health.
So first option actually offers 18k more effective health.
So unless you get hit for a number that's
between 28000 and 30333 before you shield youself, the first option is always superior.
But this bracket is so bursty that the damage you receive before you can do anything is probably so high that if it's above 28000, it is most likely going to be above 30333 too, so the second option is plainly worse.