Given that 288 will give you 10.978% hit chance, you're looking at 99.978% overall (assuming talent & raid hit bonuses). This means you'll miss about one spell in 5000. The extra 9 spellpower would likely give you somewhere around 0.3% dps increase raidbuffed. That is not much, but it's far more than you'll lose from missing every 5000th spell. On the basis of that, I would suggest you go with the extra spellpower.

In all honesty though, we're talking about numbers here which are far smaller than the margin of error of casting a few spells. It's not really going to make a whole lot of difference either way.

[EDIT: VenomByte beat me to it ]

With what precision does it calculate hit?

A number cruncher friend of mine implied some sort of quantum effect going on i.e. 99.0001-100% hit = 1% miss rate, 98.0001-99% hit = 2% miss rate but reading this thread I am lead to believe that even if that once was the case it no longer is.

Has there been any definite conclusion as to wether it is better to spec for dps and gem for hit, or spec for hit and gem for spell power?

My understanding is you always gem for dps. Spec for hit until it comes naturally with gear and then spec out.

I only gemmed and enchanted for hit when I started raiding in blue and greens that didn't have any. AFAIK you can pretty much drop a 19 SP in every slot when you are closer to cap, which isn't too difficult once you start getting 10 man items. Socketing bonuses providing SP do not grant enough to warrant gemming anything else.

Im planning to stay affliction for 3.1 and see how well it holds up untill i make any changes.
The World of Warcraft Armory

Thats a link to my warlocks current armory. So for this spec i should regem for spell damage, see where i sit as far as hit goes, and respec accordingly grabbing extra hit talents where needed?

You currently are over 17% cap, that's assuming your raid has neither SP nor Boomkin nor a single draenei ? Take this into account when calculating your needs relating to hit bonuses. In an optimal raid setting you only need personal 13% from items +talents. (14% horde side...). that's a lot of room for +SP gems, and if you ever happen to be in a 10 man raid without the extra bonuses, who cares anyway about 10 man content difficulty, you're going to beat it even missing 3% to hit.
Second point is, not taking to hit via talents is nice, to the point where you check what you can buy with said points. Fel concentration is very "meh" and not worth it. You don't even need it for farming anymore.

Any takers?

Current understanding is that it's linear. 99.5% to hit means 0.5% to miss. The easiest way to test this would be to put 1 hit rating shy of the cap and spam a dummy until you have a very large sample size. Getting statistical significance between those two will take a while.

It seems silly to have the default ragdoll calculate hit % to a hundredth of a percent if the game's just going to round the real % down to the nearest whole number.

I wonder why most ppl take the kirin tor head enchant instead of the old shatar enchant if they are short on hit. The loss of 8 spellpower is minimal compared to the gain of hit.

excuse my "noobness" but when enchantment is that again?

The Sha'tar one was Arcanum of Power. 22 spellpower and 14 hit rating, I think.

It's currently what I have been using, though I think I'm going to switch to the Kirin Tor enchant now that I got my new neck.

But honestly, instead of geming for hit, that's a much better option, atleast imo.

The Arcanum of Power is only better if you value spellpower 2.3 times more than crit.

Arcanum of Power - Arcanum of Burning Mysteries =
8 spellpower
20 crit
-14 hit (equivalent to -16.625 spellpower if you gem or gear correctly)

Talents

53/0/18 Suppression + Cataclysm
53/0/15 Malediction + 3

Talent spec > * (I dare say) This is not a conclusion, but my way of thinking. I assume this is correct, or near the best.

It should be obvious which of the above specs are superior, if one has the chance to cap hit outside the talent tree.
The last three points can either be spent for optimizing some minor damage, or spec flexibility - like waiting with spending the three talent points until you know what situation your raid is in.



Hit Chance & Probability

If there is a 10% chance to be hit by a vechicle if you run blindfolded accross a highway, you might as well be hit all the times. It is more correct to say: In 10% of the possible cases... And only if this game runs a static or smart Diminishing Returns on hit/miss, we can say that the probability is being taken care of and reassured by the game itself, making it statistically reliable.

However, while there is probability, there can only be reliability in 100%
Reliability CAN be somewhat priceless. It cannot be valued, but you can cap hit for precaution. Capping hit all the way to the 100% (yes, I know the cap is 17%) is preparing for the really shit timed misses, and possible multiple misses. Those of us who were hit capped -1% in TBC have probably all lived to see the magical 3-misses-in-a-row.

Probability is not reliable, and may as well be just as UNprobable if there is no Diminishing Returns.

I have only read Pages 1,2 & 5 so far, when making this post.



Edit:
Reliability also somewhat requires your Hit Rating to be kept away from consumables, buffs and debuffs. If you die during an encounter (be it trash or a boss) you might save the day by being hit capped when resurrected. And maybe the 3% hit debuffer is dead at some point - shit does happen.



Edit:
Let's say you have 99% chance to hit. You will do about 100 spellcasts during the encounter. Statistically, 1 of these spells will miss. However, probability does not play within the same time-limit that you are. If 2 of your spells miss, you don't have time to change the encounter so that you may do 200 spellcasts. You lost 1% DPS. And even if you get the chance to do 200 spellcasts during the encounter, there are then 100 more spellcasts that may miss. Without (or even with) Diminishing Returns, all your 1-200 spellcasts can in theory miss. This is theorycrafting.

Why do you take fel concentration instead of malediction? It's obvious which spec is superior if you go out of your way to make one of them bad. The question with the hit talents is whether or not your gear makes your DPS higher by gearing for 17% hit, or by gearing for 13/14 percent.

I don't really understand what point you're trying to make with the rest of that post.

Computer programs don't generally use decimal digits internally. The game will most likely stick the value in a 4 or 8 byte floating point variable. A 4 byte single precision float will have precision comparable to 6 decimal significant digits.

Ok guys i think my aff warlock is Hit Capped since i have 436 hit (16.62%) +1 point on supression, still while hitting the boss test dummy i don't miss any curse or spell but it still resistes some damage of them. Is this normal or did hit cap changed in 3.1?

Partial resists will always be there due to the level difference between us and the boss. Nothing can be done about it I'm afraid.

Redirect me if possible to a more accurate topic, but post 3.1 I have found that many more of my fears and casts are missing in pvp. The biggest issue being my fear fails, obviously there are many things to negate fearing but there are times when it just says miss, admittedly I haven't checked any logs to totally confirm this. So question being is there more hit rating required in pvp now post 3.1, or should I start looking into things like spell penetration?