Yes, it's probably a stupid question. I am by no means an expert.
I just finished building a system (my first build in four years) based on the X79 Dark and it passed a very important (to me) test, encoding HD video about five times faster than my old machine. So I am happy. Probably spent too much on some components (like the $350 PCI RAID card and SAS to SATA cable running a set of WD VelociRaptors because I was too cheap to spring for a 1TB SSD at this point)... but it does what I had hoped it would (encode video, and other edit tasks, a LOT faster than my old computer).
Now, I consider overclocking, which I haven't really messed with before. I'm still using the stock settings on a (six-core) Intel i7 4930K at 3.4GHz. I have 32 GB of G.Skill Trident X on board (DDR3 2400, happily timed with a good XMP profile in the BIOS - thanks EVGA!), and I already rip through tasks pretty fast, as noted above. 
For cooling, I have a Corsair H80i water cooler on the CPU, and temps don't seem to be an issue: nowhere in the system do I see temps above 85 F, even during encoding or other intensive operations. (It's all in a Rosewill Blackhawk full tower, which comes with 8 fans and lots of room around the components... nice cable management, too). Video is handled by a pair of GTX 680s (SLI enabled), and there seems to be plenty of power, there. (N.B. each card covers three slots, so I only have one more PCI slot to work with, the x8 that handles my RAID card.)
So, before I start monkeying with overclocking this beast, I thought to pose a really basic question: will overclocking make a difference in the primary mission for this box, namely HD video editing? Should I expect faster completion of tasks? Will it make the CPU run too hot for the H80i liquid cooler to keep up with?
Everything I've read about overclocking so far assumes a level of knowledge I don't have, and/or speaks in terms of benchmarks. Frankly, I don't build systems for a living, or for fun, and built this one only as a tool to do work (I am a professional videographer and photographer) because I couldn't find a stock system out there that didn't have significant potential bottlenecks, and/or potential compatibility problems with Adobe software. I could care less about what it benchmarks, the floating point calculation rate, etc. I care only about how it does the job, and hope to hear from those of you who know far better than I what benefit I might realize from overclocking in exchange for the potential to burn up more time, or, worse yet, components.

Hi and Welcome to the forums...
 
I have little doubt that OC'ing your CPU would make anything you do faster.  How much, I don't know.  I couldn't find any benchmark comparisons to see the differences.
As far as your H80 AIO cooler, you should be able to quite easily achieve a 4.2GHz OC and most likely, higher.
 
My suggestion at this point would be to wait awhile longer until EVGA puts out more of an error free BIOS revision since you're new to OC'ing and if you even decide to try it.

Yes, video encoding will decrease. I am currently in the middle of over clocking a 4930k myself.

As for, is it worth it: I am in the same boat ad well. Here's a few things you need yo remember:

The 4930k has a "turbo" of up to 3.9 GHz. But, that is only for a single core work load. Encoding uses all 12 threads you have (6 cores + hyperthreading per core = 12). So you'll be stuck around 3.4 to 3.5 on stock while encoding. Consider this your "base-line."

If you were to overclocked to a mediocre 4.2 GHz keeping all power savings enabled (Intel SpeedStep), that's an 24% increase in speed. That's huge! And 4.2 is easy to archive without batting an eye. Maybe a tiny bump in vcore. You can quickly start to see how much faster you can get. This would be an overclocked across all cores.

You're other limiting factor when encoding is your HDD. Even VelociRaptor drives in RAID 0 can't compete with a normal SSD drive in bandwidth, but especially seeking! Get under an SSD. Use your big storage to store, but use the ssd for encoding and move it to storage when done.

Now, there is a downside. The Sandy Bridge-E X79 chips' MCH was extremely sensitive to over clocks. MCH = memory controller hub. If you overclock, you most likely had to slow down your ram speeds to 1866 or so.

Now there are those with great memory that are able to run at 4.5 GHz and memory at 2400 all day long. Those are flukes! Actuslly, my 3930k runs great at 4.6 GHz and memory at 2133 all day long. Everything is left on Auto in the bios. I really lucked out.

The IB-E 4930k is supposed to allow for higher MCH speeds now, I think it is rated at 1866 whereas the 3930k SB-E was rated at only 1600.

The point is, be weary of over clocking and the memory holding you back. As a matter of fact, I'd put the memory at 1866 and go for ur biggest overclocked first. Once stable, then start to increase your memory speeds and voltages until it is stable.

1866 is nothing to laugh at either.