the easy test to judge the CPU you have (regardless of batch) is to see how much vcore it needs to get fully stable under Cinebench at 4.5 or 4.6GHz when using 25% vdroop on evga Z77 ftw (or 75% LLC on most other boards).
 
For instance if you can get 4.5GHz fully stable with let's say 1.16-1.19v vcore under load then the chances are it's a good clocker.
My 3770K can do Cinebench stable 4.7GHz with 1.21V under load
 
If you are feeling brave, another quick test is to find the lowest 5GHz bootable vcore (it just needs to boot windows and logon to user profile without crashing). most good clocking chips are able to do this below 1.35V vcore (as set in BIOS). The best ones can do this at 1.20V (aka famous batch 3218B).
 
I am running my 3770K daily at 4.9GHz on offset vcore and benching it at 5.1-5.2GHz with a fixed vcore (always 75% LLC), but the latter one calls for quite a lot of vcore (over 1.62v under load) while it can do a 5.0GHz fully Cinebench stable with only 1.46v under load.
 
My batch is pretty common among Microcenter stores, 3224B, it's totally worth the $229 they want for it
 
good batches don't guarantee the good chip, as said above, you may still get a bad clocker. good batches just increase (greatly!) your chances of getting a good clocker.
 
You might wonder how come I am running such high vcores and not mention temperatures, probably you think that my watercooling must be superior to anything ... no, I went a step further and delided my chip and replaced the stock Intel TIM (which is as good as dried out cement, meaning not at all) and used CoolLaboratory Liquid Ultra on the die and slapped it back together - this process lowers the IB i5/i7 temperatures under load by around 20-30C! couple that with decent water cooling and you can get up to 500MHz overclocking capability improvement.
 
Closed loop coolers are not bad, I know at least a few folks from OCN using them on delided chips with very nice results, but here is where the batches come into play, their chips run high clocks with low vcore, so the thermal cooling solution is a minor problem at this point.
 
Custom Watercooling will give you much better control over what you want to achieve and how, plus you can incorporate some fancy color themes or aesthetics into it as well, to each its own!
It takes time and patience to achieve "the goal", however keep in mind that you could also go with relatively inexpensive XSPC Raystorm D5 CPU kit (even an RX/EX/AX 240 radiator will do for CPU loop only) with a Dual Bay reservoir and it will be more efficient than any H80 or H100. If you plan on getting GPUs under water as well then think ahead and get bigger radiators (or more than one), but that is when it gets pricey (GPU full cover blocks are expensive, extra rads are expensive, nice compression fittings are expensive, etc.)