i5-2500k needs too much Vcore for 4.8Ghz?

[seth.i.simmons]

Just finished building my new rig (need to post it in my sig, I know!), and started into OC'ing my new i5-2500k. Here's my relevant specs:

Asus P8P67 Pro (BIOS 1850)
Intel Core i5-2500k
Corsair H60 with 2 120mm fans in push/pull
Kingston HyperX 1600mhz ram (4gbx2)

So I started out with an easy OC to 4.4Ghz (can't remember what Vcore I used exactly, but I think it was around 1.3v) and then wanted to go higher, so I bumped it up to 4.8Ghz, and added some more Vcore (again, not sure exactly how much I tried, I think it was 1.38v to start with) but I kept getting BSOD's with the 0124 code at very random times (never in game, but sometimes after quitting a game, and sometimes just idling on my desktop), and it would freeze fairly frequently at the Windows boot logo, and I would have to hard reset it. I also couldn't get it to pass Prime for more than 1hr before I got a BSOD.

So I decided to see if I could get it stable, so I read a bunch of stuff about OC'ing these chips, and on this board. I started increasing Vcore first, and got all the way to 1.425v with LLC on extreme, "CPU Current Capability" on 120%, VRM on 350Khz, and Phase control and Duty control on Extreme. Still got the BSOD and freezes on the boot logo.

Then I read about increasing QPI/VTT/VCCIO, and also read that your QPI/VTT/VCCIO should never be more than 0.5v less than your RAM voltage (my RAM runs at 1.65v, and my VTT was at 1.05v, so I was freakin out!). I immediately changed that to 1.15v, which seems to have helped a lot, as I can now pass Prime95 for 4hrs (haven't tried longer) and haven't had a BSOD yet, or a boot logo freeze (it's only been a day though, so I have my fingers crossed.

So my main questions are, is 1.425v (1.448v at full load in Prime95) too much for a constant OC (my computer only runs about 12-14hrs a day, if that changes anything)?? Plus it seems higher than what a lot of people are having to use, may just be an ok chip though, and they have awesome ones. My CPU temps currently max at 81c, with the coolest core being 74c.

And also, does your QPI/VTT/IMC/VCCIO voltage really need to be >0.5v away from your RAM voltage, or does that matter?

And lastly, my CPU doesn't seem to drop frequency or Vcore any more. Not sure why, as I've triple checked that EIST and all the C modes are still enabled. Any idea as to why that might be? And should I disable EIST or any of those modes? I would like to save some power if I could, but not at the expense of my OC

Thanks for the help, as this is my first real PC, I really don't want to kill it!

Edit: forgot to post that I also raised the PLL voltage to 1.8125v, as I had read was good to do.

 

[doz]

You be the judge. Some people run 1.4v or more daily, some swear not to. Its been discussed here with me and multiple others and Im on the abusive side of the fence I guess. Im running 1.48v loaded @ 4.9ghz.

Is 1.425v too much? To me no its not. Is it alot for that chip? I dont think so personally as a good percentage of chips wont stabalize above 4.8ghz no matter the voltage. People always say that these chips to 50x+ (the majority) and I believe that, but I dont believe they are stable (and there was a statistic that only 10% can do 50x stable on 2500/2600k's).

As far as your VCCIO being .5 away, no it doesnt. Stock voltage for it is right around 1v I believe (1.05v maybe?) and SB allows up to 1.65v ram. Maybe someone who knows more about this can respond, but that was with the previous generation i5/i7's.

 

[EarthDog]

I wouldnt go over 1.45v 24/7 personally. (see what doz was saying? )

+1 on previous gens and VTT/Dram voltage being being within .5.

I fanything, lower PLL a notch below stock...

I wouldnt worry about the power saving either.

 

[seth.i.simmons]

You be the judge. Some people run 1.4v or more daily, some swear not to. Its been discussed here with me and multiple others and Im on the abusive side of the fence I guess. Im running 1.48v loaded @ 4.9ghz.

Is 1.425v too much? To me no its not. Is it alot for that chip? I dont think so personally as a good percentage of chips wont stabalize above 4.8ghz no matter the voltage. People always say that these chips to 50x+ (the majority) and I believe that, but I dont believe they are stable (and there was a statistic that only 10% can do 50x stable on 2500/2600k's).

As far as your VCCIO being .5 away, no it doesnt. Stock voltage for it is right around 1v I believe (1.05v maybe?) and SB allows up to 1.65v ram. Maybe someone who knows more about this can respond, but that was with the previous generation i5/i7's.

That's why I had just been reading in an overclocking guide on Hardforum.com, that only 10% can do 50x+. I'm actually relatively happy with it now, still no more BSOD's or boot logo freezes!

I wouldnt go over 1.45v 24/7 personally. (see what doz was saying? )

+1 on previous gens and VTT/Dram voltage being being within .5.

I fanything, lower PLL a notch below stock...

I wouldnt worry about the power saving either.

I'll lower the VTT back to stock I guess, as it's 0.1v higher than stock right now to make it 0.5v behind the RAM.

Why would I lower PLL?? Wouldn't that hurt stability?

So should I or shouldn't I disable EIST/C1e/C3/C6??

Thanks for the help guys.

 

[EarthDog]

That number was from an Asus rep with pre release hardware... thats horse . I would bet at least 60% hit 5Ghz+ with proper cooling.

I never had to touch PLL voltage and some have said to lower it. Once you hit a certain multi, you need to enable a PLL override voltage. Not sure if they have anything to do with each other.

I leave that stuff OFF as it sometimes makes things unstable. Once you find a stable OC then enable them.

 

[doz]

50x stable ED? 60%? I dont think so..... Many people struggle to hit 50x with reasonable voltage. I agree that 60% can hit 50x, but I dont agree they are 24/7 stable. Stable enough to run a few benchies though for sure.

 

[seth.i.simmons]

That number was from an Asus rep with pre release hardware... thats horse . I would bet at least 60% hit 5Ghz+ with proper cooling.

I never had to touch PLL voltage and some have said to lower it. Once you hit a certain multi, you need to enable a PLL override voltage. Not sure if they have anything to do with each other.

I leave that stuff OFF as it sometimes makes things unstable. Once you find a stable OC then enable them.

Is a PLL override voltage just manually putting in a voltage so it doesn't automatically adjust?? If so, I already set it a notch higher, at 1.8625v, instead of 1.8v on auto. Should I lower that to 1.8v or even lower??

@doz - Yeah, I doubt many at all can hit it and run it as a 24/7 OC with any reasonable voltages. Maybe with water cooling and a lucky chip, but I don't see it with air, or self contained water cooling like my H60.

 

[EarthDog]

@ Doz - Im 4/4... . Stable as in, I can play games for hours and do whatever the fork I want without it crashing. P95? Who knows.

@ Seth - No its a switch, enabled/disabled. Again, Im not sure if they are associated. Please leave PLL voltage alone. No need to raise it.

 

[seth.i.simmons]

50x stable ED? 60%? I dont think so..... Many people struggle to hit 50x with reasonable voltage. I agree that 60% can hit 50x, but I dont agree they are 24/7 stable. Stable enough to run a few benchies though for sure.

@ Doz - Im 4/4... . Stable as in, I can play games for hours and do whatever the fork I want without it crashing. P95? Who knows.

@ Seth - No its a switch, enabled/disabled. Again, Im not sure if they are associated. Please leave PLL voltage alone. No need to raise it.

Will do, thanks for the tip. This is gonna sound really noobish, but for the life of me, I can't find where to edit my sig. I've used a lot of forums, but none with this setup. Any help would be awesome!

On a side note, do you think my temps look ok? I'm running 81c max, 74c min when running blend Prime95. Does that look ok for daily use? In-game, I don't ever break 65c, and hardly 60c even when running very demanding games like Crysis/Crysis 2, and Metro 2033.

 

[EarthDog]

User CP and its under settings and Options on the left hand side.

Temps are fine!

@doz - Yeah, I doubt many at all can hit it and run it as a 24/7 OC with any reasonable voltages. Maybe with water cooling and a lucky chip, but I don't see it with air, or self contained water cooling like my H60.

Of course not on air or those smallish self contanied water units that only cool as good as high end air. Custom water though...yes. We are not talking extreme cooling though...and we are talking the chip. 3 of my 4 were retail non cherry picked chips too.

 

[seth.i.simmons]

User CP and its under settings and Options on the left hand side.

Temps are fine!

Thanks so much, you were a huge help!

 

[Bisquit]

Interesting read!

I can tell you my plain p8p67 board does 48x with all settings at default, only vcore needs to be adjusted, or finetuned with a manual value or through offset.
That seems to sound like magic, but isn't, above 4.6Ghz I really need to focus on the vcore and breaking 1.4v for cpu is done easy in such cases.
I'm guessing not only cpu's of the same type differ, but also mainboards of the same type and chipset. Could be totally wrong though.
On a side note, llc and the other settings doesn't seem to do anything at all if I alter them, haven't touched llc overvoltage though, it's quite possible my bios is fine as is, but perhaps a bit flawed, I find this also when I load a profile, it messes my settings up and only after applying the profile again does it stick with the correct settings. Still, my board is solid so I see no reason to update the bios, yet.

As for temps and voltages, reading around wil give various opinions and ideas as what is good for you, and that's what matters after all.
Your games wont see any difference between 3.8 and 4.8Ghz on sandy bridge, maybe the occasional cpu hog that does profit from a mild overclock.
So it's all in the numbers where you feel fine with.
I like my vcore below 1.3, or just at that, I also like my temps to stay below 75°C when stressing with prime95, summer or winter, and I found I have these things with 4.5Ghz.

Maybe later I decide if I need more or want more, prolly need a better and more expensive cooling system also. But the gain in megahertz is not as big as a new cpu architecture, therefor I expect little gain in adding 3 or 400Mhz.

 

[seth.i.simmons]

Interesting read!

I can tell you my plain p8p67 board does 48x with all settings at default, only vcore needs to be adjusted, or finetuned with a manual value or through offset.
That seems to sound like magic, but isn't, above 4.6Ghz I really need to focus on the vcore and breaking 1.4v for cpu is done easy in such cases.
I'm guessing not only cpu's of the same type differ, but also mainboards of the same type and chipset. Could be totally wrong though.
On a side note, llc and the other settings doesn't seem to do anything at all if I alter them, haven't touched llc overvoltage though, it's quite possible my bios is fine as is, but perhaps a bit flawed, I find this also when I load a profile, it messes my settings up and only after applying the profile again does it stick with the correct settings. Still, my board is solid so I see no reason to update the bios, yet.

As for temps and voltages, reading around wil give various opinions and ideas as what is good for you, and that's what matters after all.
Your games wont see any difference between 3.8 and 4.8Ghz on sandy bridge, maybe the occasional cpu hog that does profit from a mild overclock.
So it's all in the numbers where you feel fine with.
I like my vcore below 1.3, or just at that, I also like my temps to stay below 75°C when stressing with prime95, summer or winter, and I found I have these things with 4.5Ghz.

Maybe later I decide if I need more or want more, prolly need a better and more expensive cooling system also. But the gain in megahertz is not as big as a new cpu architecture, therefor I expect little gain in adding 3 or 400Mhz.

I definitely agree with you on that, I would love to keep mine at 3.8/4Ghz, but I do a lot of video transcoding, and the boost in Mhz REALLY helps. Plus my temps are still very reasonable, and its summer (and 101 degrees at that!), so they're only going to drop from here.

I might try resetting most of the various settings besides Vcore and see if I can still get it stable, but I am definitely going to drop the PLL voltage, and try dropping the LLC and maybe the Vcore a little too, if I can. Just would like to get my voltages closer to 4v at load, if at all possible. I'll try messing around with it, and update yall if I can get it any more "refined".

Thanks again for all the help.

 

[seth.i.simmons]

I might try resetting most of the various settings besides Vcore and see if I can still get it stable, but I am definitely going to drop the PLL voltage, and try dropping the LLC and maybe the Vcore a little too, if I can. Just would like to get my voltages closer to 4v at load, if at all possible. I'll try messing around with it, and update yall if I can get it any more "refined".

Thanks again for all the help.

So I've been messing with the OC all day, trying various different settings, and then testing with Prime95. So far, I haven't been able to drop the Vcore or LLC AT ALL, as I get a 0101 BSOD code doing Prime95 either way. Tried dropping the LLC 25%, and it BSOD'd, then tried dropping the Vcore .05v, and got the same BSOD.

I was able to drop my CPU Current Capability to 110%, lower Duty Control from Extreme to T. Probe, lower Phase Control from Extreme to Optimized, and lower VTT and PLL voltages back to Auto(and change PLL overvoltage to Auto instead of Enabled). So far, it's the most stable I've ever had, and I can Prime95 perfectly, with no BSOD's.

Thanks for all the help guys!

 

[seth.i.simmons]

Sorry if this is too many consecutive posts, but I'm having a new issue.

For some reason, even though my OC is totally Prime95 stable, I can't get it to stop BSOD'ing when at idle (only thing running is uTorrent). Every time, I come back a little while later after leaving it alone, and it has a x0124 BSOD. Which usually means an increased Vcore, but it runs perfect at full load! Any help fixing this would be awesome, as I can't seem to find any info anywhere on it.

 

[EarthDog]

We do have an edit button...

Im guessing you have LLC enabled, right? When you have LLC enabled, sometimes the voltage under load goes UP from what it is idle/what you set it at. Try increasing the vcore 1 notch and lowering the LLC level 1 notch (or leave LLC alone).

 

[seth.i.simmons]

We do have an edit button...

Im guessing you have LLC enabled, right? When you have LLC enabled, sometimes the voltage under load goes UP from what it is idle/what you set it at. Try increasing the vcore 1 notch and lowering the LLC level 1 notch (or leave LLC alone).

Yeah, sorry, I just thought it would be better to post again so people would know there was an update/new problem.

I actually tried that yesterday in my attempt to lower the voltage/LLC some, and tried increasing Vcore and lowering LLC. When I put LLC at anything other than Extreme/100%, it wouldn't raise voltage at all under load. It would stay at 1.424v, even with the Vcore set at 1.435v, and LLC at 75%/Ultra High. Not sure whats up with that, but I couldn't get it to pass prime at all, and that's raising the voltage .01v, and only dropping the LLC one step, which is 25%.

I'm reading through this thread, and am thinking about turning LLC off, and maybe boosting the Vcore to 1.4v or maybe 1.45v.

 

[EarthDog]

You can disable all together sure. Here is the concern with that...which really isnt a concern, but higher idle voltage.

Just make sure if you do that when you load the CPU that the vdroop matches your current stable LLC voltage.

 

[seth.i.simmons]

You can disable all together sure. Here is the concern with that...which really isnt a concern, but higher idle voltage.

Just make sure if you do that when you load the CPU that the vdroop matches your current stable LLC voltage.

Yep, thats what I'm reading right now, is that I would probably need 1.45v, since my stable Prime voltage is 1.44v/1.448v (kinda alternates back and forth) to compensate for vdroop. I'm gonna try that out, and see if it seems to help at all.