I've done extremely limited experiments on various proc rates in TBC and it seems that at least those items and enchants which I have thus far tried appear to have a cooldown on the proc. Following is largely speculation pending more thorough investigation but I felt this was the appropriate place to find out if someone's either done some testing on this already or has other information to contribute to the subject.

I've really only tested on procs that grant a temporary short duration buff (such as spellsurge enchant in beta or Bangle of Endless Blessings in release). It seems to me that these buffs have a definite cooldown - I've been unable to proc them twice in close succession.

Spellsurge enchant text implies that the proc rate would be 3% but on beta servers already the enchant was data mined to have approximately 15% proc rate (which to me seemed to hold as long as made certain that I was outside of the proc cooldown period). During beta I arrived to a cooldown of 30 seconds for spellsurge proc (3 times buff duration). On bangle of endless blessings the cooldown seems like 45 seconds (still 3 times buff duration).

This sort of behaviour makes sense: it doesn't particularly favor fast spell casts or fast attack speed though those generally do end up benefiting from it somewhat more still similar to leader of the pack. Obviously the mechanics are a bit too complicated to be printed in the tooltip so a vague "chance to proc" would be written.

If the pattern holds mongoose enchant would have 45 second cooldown also.

A final related observation is that items with "use" that grant similar buffs tend to have a cooldown of exactly 6 times the buff length (there are exceptions such as items that give temporary health boost). One could conjecture that the exact same item could be implemented as either proc (with proc cooldown of 3x buff duration) or as "use" (with use cooldown of 6x buff duration) and that these would be considered equal. Items that give proc would have better uptime on buff but lack control over timing. The ratio of static vs buff based stats probably then lies somewhere between 1:3 and 1:6. My guess is that it's 1:5 - I mean that 30 attack power on an item could be replaced with "use: 150 attack power" with maximum of 1/6 uptime. In right situation use and proc based items are probably slightly stronger than static bonuses.

At this stage I've no hard evidence but at least to me this makes sense. I realize much of what I've said is at this stage simply guesswork and my numbers might be very far off.

Any thoughts?

Don't have much to add except that I think you're onto something.

I certainly can't recall Omen of Clarity proccing twice in a row like it used to.

Clearcasting for mages certainly doesn't have a cooldown - I've often cast a clearcasted fireblast and immediately gotten another clearcast.

Would make sense with trying to stop potential burst damage. Prolly should design an addon to track the minimum time between procs and see what can be figured out. The difference between clearcasting and omen of clarity, is with omen of clarity procs I can spam shred on you every second if OOC keeps proccing instead of every 4 seconds if it doesn't. So not too surprising Clearcasting wouldn't since its only effecting mana use and not really burst DPS.

Windfury has a hidden proc cooldown. Estimated at 3 seconds.

When duel wielding only is what I recall nite_moogle saying in the shaman thread.

It's even with weilding a slow two hander.

Could you be more specific?

Haste proc from the T1 master Macesmith epic hammer does -not- have a cooldown, unless it has one under it's own swing timer (as I've gotten 2 procs in under 1 second).

Nightfall does not have a cooldown.

I figure you are talking about this one then. Good old Crusader atleast has not recieved any limitations like this, though it scales down from what I hear (haven't checked properly yet).

They certainly have the capability to give procs cool downs. Some items have it spelled out explicitly like the trinkets from the underbog quest. They give 200 life or mana when you get a kill and the effect cannot happen more than once every 10 seconds.

Edit - http://www.thottbot.com/?i=57334

As was mentioned the Windfury cooldown is 3 seconds per rank of an enchant, using Windfury 4 on the main hand and 3 on the off hand clearly bypasses this occurrence.

I've also noted while leveling my paladin that Seal of Righteousness can cause a hit to double-proc Fiery enchant (proccing both off the white damage and the yellow damage) but if the weapon itself has a proc that fires on hit, the weapon proc never occurs with a double proc of Fiery (you never get hit+SoR+proc+fiery+fiery). There are definitely a lot of hidden mechanics still in place that we don't know about.

I had it proc 2 times in a row several times since TBC went live.

This wasn't on ym own druid since im playing my paladin though, but it shouldn't make any difference from char to char.

One of my guild enchanters has the formula, once I get a weapon worth enchanting I may just get spellsurge and test it. If the proc rate is really 15%, and if it procs off stuff like water shield casts it may be really good for shaman. If it can proc off totem casts, it's the holy grail (if it can proc off Totemic Recall, it goes beyond Holy Grail). Heck, it would even add to the "free rank 1 lighting bolt with totem of lightning while I regen and hope for a clearcasting proc" tactic.

At any rate, it shouldn't be too difficult with a shaman to test within an hour whether the thing can proc twice within 10 seconds.

Using Shiffar's Nexus-Horn (35% proc on crits) as a frost mage and chaining crits all over with shatter, nova, water elemental freeze and AoE etc. I very frequently proc it and I stand a very good chance to force a proc through if I deliberately aim for it. Initially, I tried to change my playing style to chain-proc it but it only took me a few hours to notice a very apparent pattern that it would never proc while the effect was going on. I also noticed that the duration was actually 15 seconds and figured the extension beyond the tooltip might be some sort of compensation for the downtime by that hidden feature.

Coming to think of it, I've not only been unable to refresh it while it was active but I haven't ever procced it in the few seconds after the effect expired and I have been using it for days now. I can't at all pinpoint the cooldown but your theory seems extremely probable.

Sorry for the slight derail, has anyone tried spellsurge with non-DD spells? The zang token trinket that restores mana on spell hits doesn't seem to work on dots at all, for example :(

Yep, done some testing with hitting something and waiting for it to proc, then immediatly after it fades cold blood mutilating with snd up. normally gives 3 or 4 crits in the space of 2 seconds. I've NEVER been able to get it to proc off them.

That's the first thing I thought of, as well. It's probably a pipe-dream, and low-priority at best, but I'd love to see consistent wording for effects.

I have had it proc at most I think ~10 seconds in between. I havent really paid attention to it and it does seem to have a low proc rate considering the amount of crits I put out (though it makes sense, otherwise 4 WW crits would proc it almost everytime, no?).
Now that the threads OT has been mentioned I'll keep an eye on it and see. I am almost positive I havent seen it refresh itself either.

Somewhat offtopic but I heard just random gossip that HoJ's procrate got nerfed with the leveling up? I never heard anything of the sort and dont really see how they interact together (ex: crusaders proc rate didnt get nerfed, but the effect did, and you cant really change HoJ's effect since its based on your weapon).
Just wondering if anyone else heard something similar from a reliable source with something to back it up.
Thanks

I'm pretty sure that this is incorrect. While leveling recently with a Searingblade with a fiery enchant, I was getting so many double procs with SoC and the blade going off that I starting taking screen shots... When I get home I'll rummage through them and post one showing the effect... Obviously its rare, but it does happen...

I retract this, I had it happen last night at last.