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4970k OC stability issues - system agent?

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New Member
Sep 18, 2016
Hi all,

I've been (for quite a while now) trying to get my 4970k OC stable - which has been a headache to say the least.

It's been a learning curve and as such, I've only recently started messing around with XMP etc

It seems my memory/timings etc are somewhat to blame - (memory is 2666) - so I'm currently looking at the system agent / digital/analog I/O voltages as I had previously never touched these.

So far (although I've not finished) it seems to be helping with XMP on.

I just wanted to check I'm along the right path...

XMP on, voltage manual @ 1.275
Multi: 47
System Agent: 1.064 (was 0.936)
Analog I/O: 1.132 (was 1.012)
Digital I/O: 1.132 (was 1.012)

XMP would cause prime95 v27.7 to crash within 5 minutes previously. Now it's going quite a bit past that.

IF its still unstable... what should I continue to increase? if anything....



Sep 21, 2016
I'm absolutely two left thumbs but I think long periods of Time on Prime95 is overated. Prime95 is a Synthetic
almost nothing that the average user or Gamer is are using in the real world comes close to using those kind of resources.

I have my I4790 CPU stable OC to 4.7ghz but my memory is running at 2200mhz.

Also on the forums you find that Asus and others do not recommend using it with Haswell Architecture.
1 minutes on prime at all settings is enough for me as long as it passes the other tests.

As for Ram, run OCCT Large Medium and Small . BTW OCCT is really good at detecting memory mistiming
within 25 Seconds it will always detect obvious problem. So save time by beginning with OCCT and
running through it's paces

The other I like is
Intel Burn Test

If it fails
Hey you can raise the bridge or lower the river.

Try lowering your Ram Speed. My Ram is rated Pc-2400 At 2400mz Using XMP Settings my PC would fail both OCCT
and Prime 95 blend.

Lowered my XMP setting to 1.66mhz it passed and kept raising it to 2200mhz.
So I can spend days playing around with the RAM or just accept a slightly lower MHZ many say that
lower Ram Speed doesn't have much of an impact on the system.

Good Luck

Because my processor is Haswell I never use prime Low fft for more than a minute or so. It is alleged to overvolt the CPU

Also what are you using to monitor your system,many that the products from CPUID System Monitor doesn't like prime
use different program. I'm on my Linux now so I don't have ready availability to the program

My suggestion is that if your machine withstands 10 passes of the Intel Burn Test and OCCT 3 minutes on small medium and largee you are good to go.

If you run into problems while gaming or doing intensive Video Rendering then you would have to re-think it.
Last edited:


Dec 10, 2003
I'm absolutely two left thumbs but I think long periods of Time on Prime95 is overated. Prime95 is a Synthetic
almost nothing that the average user or Gamer is are using in the real world comes close to using those kind of resources.
Prime95 is not Synthetic it is all math calculations with a check and balance.
All a CPU does is crunch numbers, that is it! All you need is a good math program to test all the transistors. When encoding, Graphics and physics calculations you can get by with a unstable CPU or memory you don't need exact numbers to run. Another good thing about testing a CPU with math there is no overhead with the software the Prime95 program can feed the CPU as fast as it will go.


Sep 21, 2016
Hi Wingman you bring up a good question that I've been wondering.

Is running numbers the way that Prime does representative of what you'd encounter in the real world
or is it far above?
What types of programs crunch numbers the same way.?

BTW I misread his post, I thought he said 5 hours.

What in the real world would stress a CPU that far.


Dec 10, 2003
All a CPU does is crunch numbers that is how they work. Apps and programs are all numbers when you get down to the base code, the processor only takes math to process. All programs run in the real word and prime95 is just a program like the rest however it loads the CPU 100%. It is very complicated to explain however I'm going to make it simple if there is any stability hardware failure you have a problem, Intel and other companies can't make a Processor that fails to the best of there ability. If you drive a new car the air bags, brakes steering, engine, is controlled with a Processor. Computers run the internet, servers, calculate medicine, Auto CAD, scientific computing, just about anything.

Now if you don't use your PC that much and you don't mind lockups every once in a while that is your choice. So what i'm trying to say is don't blame prime95 program for any problems, a lot folks that overclock don't like prime95 because they can't pass it, then they find out the hard-way with stability problems and lockups.

My PC runs and games 24/7 zero problems zero lockups, I tested overclocking stability the best I can with Prime95 blend.:)


Jun 5, 2009
Sydney, Australia
@OP, can you please post your entire system specs? Cooler, Board, Actual RAM Model, etc. Better yet fill out a signature in your profile to list your specs instead.