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Why is my 2600K so poor?

Phemo

Phemo

Phemo

Soldato
Joined
6 May 2004
Posts
6,092
Location
Fareham
Hi guys,

I'm running a 4 year old Asus P8Z68-V Pro with an i7 2600K. I remember never having too much luck getting it running a stable overclock back when I bought it and shortly after I sold my graphics card due to not having the time to play PC games anyway. However recently I've just bought a GTX 970 so have been tinkering with my overclock again but once again I'm not having much luck.

Specs are:
i7 2600K
Asus P8Z68-V Pro
OCZ 700w PSU
4x4GB sticks of Kingston Genesis 1600MHz
Corsair A70 heatsink

Now of course I know all CPUs are different and it is quite possible that mine is just one of the bad ones but from some skim reading even the 'poor' ones will do in excess of 4GHz with ease.

I just can't seem to get mine stable at even 4GHz - 40x multiplier and stock 100MHz bclk obviously. I've had the core voltage up in steps all the way up to 1.4v and it will still fail Prime testing within an hour or so, or more commonly, it'll just reboot itself. I've got the load line calibration on extreme, memory timings all forced to what they should be and I've played around with various other settings to no avail. I've also tried removing 2 of the sticks of RAM to see if that helps but it made no difference.

CPU temps seem to be reasonable - at 4GHz under Prime load it's topping out at around 65 degrees C so I'm not too concerned about that. All the voltage rails on the PSU seem to be rock solid and spot on for what they should be also.

So, do I just have one of the really poor 2600Ks, is it my motherboard or am I just missing something here? I'm planning on upgrading to a Skylake i7 when they're out but just fancied tinkering around with this setup again.

Any help would be appreciated.

Edit: Really I should've posted this in the overclocking forum. Could a mod please move it for me? Thanks.
 
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doubt its the board,i have the exact same one and it ran my 2600k at 4.5ghz sweet as a nut,and now runs a 2700k at 4.8ghz no probs

you'll find you probably need more vccio voltage with 16gb of ram more than extra cpu voltage

for 4.5ghz you'd need around 1.35v cpu voltage,and with 16gb of ram you'd need around 1.15-1.18v vccio voltage

if your clocking to 4ghz you might only need around 1.25-1.3v cpu voltage and 1.15-1.18v vccio

llc should be set to either medium or high

here's an old guide I posted,but enter own ram speed/timings/dram voltage and manually set vccio at around 1.15v http://forums.tweaktown.com/asus/47510-asus-z68-v-pro-4-5ghz-bios-screenshots.html
 
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After 4 years my 4.5 ghz 2600k and a gigabyte z68 ud3p started to get flakey from cold boots. After months of testing my vtt voltage needed tweaking from 1.05 to 1.175v.
It's been fine since.

Might be something to look into on yours
 
Yeah I would agree about the VCCIO - my 2700K needs 1.15v to run @ 4.8GHz (1.37vcore). I also have Internal PLL overvolting enabled but shouldn't need that for 4GHz...
 
Thanks a lot for the help guys. I upped vccio to 1.15v, left LLC on high, put the cpu voltage offset to +0.005v and 4GHz managed to run Prime all night so that's definite progress. Now to try 4.2GHz :)
 
I ended up with my offset running +0.025 so expect it to go higher. Great progress BTW :) I wouldn't bother with prime through, download & install RealBench. It'll test the CPU far closer to your general usage than simply torturing it with IBT or Prime! :)
 
I have same mobo & CPU. Looking at my notes here are the things that I changed to make OCing magically work:

-spread spectrum enabled
-set short/long power limits back to auto
-cpu current capability 140
-ram volts/clocks manual

My notes are very hard to read so even I am not sure what exactly I did. :D But thought I'd post it and see what people say.
 
I think I was using these:

High llc
cpu voltage offset mode
+0.025v in offset
cpu current capability 120%
phase control extreme
Disable Turbo
 
Mine's running at 4.8 forever. I had it at 5Ghz for a while too by tweaking, but the 4.8 I have here is from the 'auto' settings it calculates when you change just the multiplier, as i had wiped my settings at some point and couldn't be bothered re-discovering them :-)

Best piece of CPU/mobo I've ever bought!
 
Thanks for the help guys and I'll give RealBench a go. I got my CPU prime stable at 4.5GHz - left it for 15 hours and it was fine but it doesn't seem to be stable in games. When playing GTA V I randomly get an error saying gtav.exe has stopped working and it bombs out to desktop. It has lasted an hour or so but it doesn't appear to do it when at stock speeds. Whether that's fluke or not and it's a game related issue I've still yet to work out - wouldn't surprise me if it was the game as I've read of people having that issue with multiple sound devices installed. Reason I think that is because it did it with the CPU at 4.5, then I tried 4.4, 4.2 and 4.0 before just dropping back to stock.
 
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Game stability is a real problem, prime won't prepare you for it. :)

I think GTA is one of the ones that are harder to get stable. About all you can do is increase vcore I think. But it's a PITA checking game stability, you will have to play for extended periods (over an hour). :(
 
does it crash to desktop in other games?

look in event viewer to see what caused the crash,it could be app error?

might need few more clicks vccio idk till you test (and or more cpu offset)
 
Trying to sort out a decent/stable OC on mine at the moment (Board & CPU in sig) but can not for the life of me get it stable even at 4GHz...

I don't have "VCCIO" nor can I find anything to do with "VTT" either in my bios.

I have tried a basic 4GHz OC with offset +0.005 and no problems at all running either lengthy Prime passes or Realbench. It's in game that I just end up getting BSOD at random times.

Oh and like the OP I am also running 16GB memory but via 2x 8GB sticks.

Any help please? (Thought i'd post in here seeing as the OP seems to have sorted theirs out :) )

Thanks in advance
 
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I have mine running at 4.6ghz using 1.37v.

Even though it's on watercooling it doesn't like going much higher than that though. You shouldn't go over 1.4v with them afaik.
 
wazza300 said:
@digit look for vccio or vccsa (system agent )

Whichever ones running at around 1.05v raise it to around 1.15v
Click to expand...

Yeah i have VCCSA and it is set to 1.050v by default. So when you say set it to 1.15v, you mean 1.150v yeah?

Thanks again
 
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