You may have to set up a water loop bro, the hit that 5.0, but it IS doable. My 6850 chips, both of them, are very content at 4.4 with the NZXT Kraken, IMO one of the top 3 or even 2 AIO coolers under 150$ (Swiftech IMO make the best AIO for the $, but for that money you can build a custom look, or at least get a good start on it). I have the EK blocks for the 1080 cards, pumps, fittings, etc, so just need stuff for the CPU and a few other nicknacks and I'll report in on custom loop o/C with the 6850.
I tried two 6800 chips as I thought I had a poor o/c one, but nope, it seems they are happy at 4.0, a modest O/C, and CAN be pushed to 4.4, but the results aren't much more impressive than the 4.0 results, and it's a giant PITA for power/v settings and keeping 4.4 stable, so I've left mine at a happy 4.0, and that little 6800 performs very close to the 6700k in games, wipes the floor with it in apps, and is close to the same $. The whole PCI E lane issue with SLI and m.2/other SSDs I discussed in another thread, and my tests showed that you lose nothing really due to the lane issue running SLI in games that I can tell.
I do NOT have a a 6950x yet, Jess still has her 5960x, and looks at me cross eyes, pulls faces, and flips me the bird when I tell her she's not "Jenny from the block" with last year's (3 years but whatever) CPU, and should drop the $to get it (so I can test and mess with it, ha ha). We'll get one either way soon next trip back home and to the PC shop we use. I'll be right there with you trying for 5k, because it's going to be a custom loop aaache toooo oooh system right from the gate.
As I've said a few times now, no question, the 6700k Skylake platform is slightly superior in fps at least over the 6800/6850 platform, and cost a bit less too, although not all that much for the 6800. Editing videos, and doing all that tehcie stuff is where they do shine. Personally, when the next Skylake platform comes, I'll probably sell/trade the Broadwell E systems other than the 6950x we'll have by then, go new Skylake, and go single 1080ti or 1080Titan instead of SLI - SLI , NEVER AGAIN. It's the land of Israel chant for me regarding that setup. NO MO.