Set all voltages to manual. (VCCIN 1.95v, Vcore 1.275, Vcache 1.15, SA 1.05, VCCIO CPU and PCH 1.05, PCH CORE 1.05, PCH I/O 1.5)
Set load-line calibration (vdroop) to Level 3.
Don't exceed the following voltages.
https://www.overclock.net/threads/struggle-with-overclocking-the-6950x.1745860/page-2#post-28423892
CPU to 40
Cache to 35
Download Prime95 and HWINFO64
Use prime 95 to stress test (20min) and watch your CPU temps.
If you're stable, increase cpu frequency until unstable.
Then increase cache/uncore until unstable.
If your CPU cores are under 85-90C, you can increase core voltage.
Most people can get 4.0-4.5Ghz core & at least 3.5 Ghz uncore/cache.
For ram, I recommend getting 3200 or 3600mhz crucial ddr4. You will want to manually set the clockspeed to 3200 as that's the fastest X99 will handle. 4x8GB is best because that's single rank quad channel. An overclocked 5960x is about as powerful as a Ryzen 2700X-3700X depending on the task but with more power consumption.
One more thing, 6950x are going for about 300 USD on ebay and aliexpress. If you install one into your ASUS board, the mobo will apply a 4ghz overclock. Add a 3200mhz ram kit and you're pretty close to maxed out. So if you don't want to deal with the hassle of overclocking and stress testing, it might make sense to just upgrade cpu and ram. (make sure you still set voltages to manual as these motherboards are known to overvolt and kill the cpu)