OC on my new 980 BE

You might try upping the NB to 2600mhz, then run some tests. If you feel lucky, bump it up to 3000mhz because that will result in massive increases in memory throughput. Some motherboards can handle it, some cant.
Setting the ACC to +2% for all cores allowed me to get 4300mhz out of my 970T @ 1.475vcore just fyi. As for prime, you'll want to see how long it lasts, but its not always the right tool for the job. Great for production enviroment servers to make sure you dont have any flaws that could bring down the new exchange server, great tool to find your max temps with the cooler as well. But sounds like you've got decent air cooler, so you should be ok.

A alternate way if you cant pass the magical prime mandate, is to find out if you've achieved a stable overclock by simply normal use of the computer on your desired overclock for a week or two or three. If it doesnt crash and it doesnt BSOD, temps are within range, and you can run all your programs and games without issues, you can consider it stable. I'd recommend a few programs for consistant monitoring:

1) Core-Temp - shows real time core temps in the notification area.
2) CPUZ (of course)
3) HWMonitor
4) AIDA64 v2.3 extreme edition (very detailed system information, including an integrated stability/stress test)
5) SiSoftware Sandra Professional Business (x86)

good luck

Yeah, I agree that he might want to increase his CPUNB frequency eventually but let's get him on track with the basics first.

I did get 3.9Ghz at everything stock and Prime95 ran for over 2 hours. At 4.0Ghz it ran Prime95 for about 30 min and then starting acting up. When I upped the CPU voltage, it ran Prime95 for awhile.

hey I'm following this because I have the same cpu and cooler.

right now I have 4 ghz, 1.41 voltage, 2400 mhz nb, 2000 hyper, 1333 ram, and 9/9/9/24/33 stepping.

Prime95 is running right now. It has been running for 10 min and so far so good. I'm at 4.0Ghz at 1.4375v which is very close to stock. Only changes so far is what trents suggested. That was change the CPUNB voltage to 1.25 and set the CPUNB Freg to 2400

This is what I got. I took these images while Prime95 was running. What would be the next thing to do? It seemed pretty stable.

madman, what is your CPU/NB voltage set to now? And what is your memory voltage set to? Often, the Deneb core CPUs have trouble running the ram at 1600 mhz. The integrated memory controller (ICM) was a little weak.

I set the CPUNB voltage to 1.25v as you suggested earlier. My ram is set to 1.66v. I just ran Prime95 again for 20 mins and it ran fine. CPU core temps went to around 52C.

madman he's saying there's no reason to overclock your ram to 1600 mhz (you have that right now) just go to 1333. this will help in your overclock too.

Do you have Cool N Quiet and C1E disabled in bios? If not, do so. Also, go into Windows Control Panel Power Options and set the power scheme to High Performance. That should turn off all the green, throttle-down energy saving stuff that messes with overclocking in the higher ranges.

Now, it's just a matter of stress testing and adjusting CPU frequencies up and core voltages up to get stability back if necessary. The only other thing I would have you think about is lowering your memory frequency from 1600 to 1333. That might give you a little higher overclock on the CPU. Deneb core CPUs don't have a real strong integrated memory controller (ICM) and many of them won't run ram at 1600 mhz and be stable. Maybe yours will.

Also, watch your temps. Core temps at 52c is close to what is considered the temp stability wall of around 55c. You may have just a wee more room to add some CPU core voltage.

Yes, Cool n Quiet and C!E are disabled. Also in Windows, I'm set to high performance. That stuff was set that way when I set up this system. I changed the memory to 1333(669 Mhz). I've never had any trouble with my system with the 1600 memory settings even though I used a X4 945 125w CPU for over a year until I upgraded to this 980BE. Should I go to 4.1Ghz and try it or should I run Prime95 longer? What's your thoughts on the next step(s)?
One thing that has me thinking. Is there a way to have the CPU fan run full speed all the time?

At this upper end of the overclock range you need to verify that the system is really stable with Prime95 blend runs of at least 2 hours. If so, go for a little more. I wasn't suggesting you should lower your memory speed necessarily but I just wanted you to think about it in the equation. There is some doubt as to whether or not the Deneb core CPUs even benefit much from the extra memory bandwidth at 1600 mhz. anyway.

This is what happened after about 1.5 hrs of Prime95. Do I need to increase the CPU voltage or increase some other setting? Not sure what it means.

Typically, it means a smidgen more CPU voltage is needed. You are close. The next vcore (CPU voltage) bump will probably be all your temps will stand so whatever overclock speed you are now at is probably the end of the line.

What about upping the CPUNB Freq. to 2600? The next setting I have is 2600.
Is there any way to have the CPU fan run at full speed instead of changing speeds?

Okay, I don't remember what CPU cooler you have so it's time you put your system info in some detail in your "Sig". This is a common courtesy on the forum because this very thing happens when threads start to get long. Go to the top of the page and click on Quick Links and then Edit Signature. You can use mine if your want a pattern to refer to for an example.

The first time Prime95 failed, I turned the memory back to 1600. I'm running it now with the memory at 1333 and Prime95 has run for over 2 hrs and still going strong. I guess it doesn't like the 1600 memory speed. Temps still hovering around 51-52C. My sig is now available. How about the fan speed?

Well, it obviously will work okay with the memory set to 1600 mhz at a certain CPU overclock level but probably has a limiting effect on the final overclock level. Running the ram at 1600 mhz just puts a little more strain on the ICM, that's all.

Does the Hyper 212 Evo cooler have a 3 pin or a 4 pin fan wire? If it has a 4 pin fan wire you can program the fan speed progression in bios, usually in a section called "PC Health". If its a 3 pin, no. It may have a thermal diode in the fan hub, however that causes it to go faster at higher environment temps. How fast is the fan rated to spin? How fast is it going?

The fan has 4 pin fan wire. I got about 2.5 hrs om Prime95 with no problems so I shut it down. I'll leave the memory at 1333 since it doesn't add to the performance. The temps stayed around 50-52C. Mostly running around 50-51C. Should I try 4.1Ghz and maybe change the CPUNB Freq to 2600 or just try 4.1Ghz? Maybe I'm at the limit? Your thoughts would be much appreciated. BTW, thanks for all the help so far.