Very strange overclocking experience - can anyone explain?

[dakrazeedude]

Hello everyone,
About 2 weeks ago I reached a stable 4.4 ghz with my 4670k at about 1.259 vcore (1.2614 under heavy load).
However, since yesterday it has lost its stability, crashing with a medium load (like unintensive games).
As I changed the settings in the BIOS I decided to try to run at 1.25 vcore (which in the past was enough only for the lightest of loads) and to my amazement, it runs stable!
I haven't changed anything from the first attempt and now I am completley confused.
For short, I have no idea why I lost stability, or why reducing the voltage re-granted it.

Can anyone explain this?
Thanks.

Additional info:
Motherboard: Asus ROG Gene VI
Overclocking in manual mode (no offset or adaptive), with LLC set at max (tested max vcore at 1.2614)
550w seasonic bronze rated PSU (~6 months old)
note: temperatures never exceed 72C, even when stress testing.

 

[InvalidError]

That is called burn-in or breaking-in.

You take a component, characterize it fresh out-of-the-box, make it run for a while, re-characterize it and you may get a different set of results.

 

[geofelt]

You may have been on the borderline of stability.
What did you use to test? Some do not test all parts of the cpu enough.
I use OCCT. Stress test for long enough so that the temperature rise becomes stable.
Then back off one multiplier and run with it.

Under normal usage, you will not get to that level.

 

[dakrazeedude]

Hi, and thanks for the quick answers.
I used Realbench for stress testing, followed by CPU intesive games.
In all my tests, temperature rised gradually but would stop at 72 celsius.
Am I supposed to worry?
Thanks

 

[InvalidError]

72C is a bit hot but not really a problem.

 

[dakrazeedude]

It shouldn't be from what I read. Also, it only reaches such temps for brief periods while gaming. It usually stays around 65-68. And that's with the previous settings - meaning +0.1 Vcore.
To sum things up, is this normal?
Thanks

 

[InvalidError]

To sum things up, is this normal?Thanks

If you are managing 4.4GHz on the stock cooler and only hitting 72C, that would be pretty good.

If you are using an aftermarket cooler then it is not so good..

 

[dakrazeedude]

I'm using Coolermaster 212 evo.
I'm checking temps in CoreTemp and in shows 42 degrees to Tjmax.
Is it too high?
As a side note, I live in a hot area, so it's also a factor.

 

[Dark Lord of Tech]

What card do you run.

 

[dakrazeedude]

What do you mean by card?

 

[dakrazeedude]

Hi and sorry for the long response time ( I was away).
I took note of the temperatures and toned the overclocked down a bit (4.3 ghz).
I also gave the GPU a more agressive fan curve to avoid it spreading heat (@Blackbird I thought that's what you meant, sorry if I'm wrong).
Thank you both for helping me.