• We’re currently investigating an issue related to the forum theme and styling that is impacting page layout and visual formatting. The problem has been identified, and we are actively working on a resolution. There is no impact to user data or functionality, this is strictly a front-end display issue. We’ll post an update once the fix has been deployed. Thanks for your patience while we get this sorted.

need help with oc on i 2500k and intel mobo.

philipma1957

philipma1957

Golden Member
I just set my machine up today and I pulled the stock cpu cooler put on an evo 212 and temps dropped 12c. so I feel I could try a slight oc 4.0 or 4.1


I have an intel mobo dp67bg


the cpu is set at 100 mhz and 37 multipler.

how do I set it it to go to 4.0 do 105 x 38 gets me 3.99. I have not done bios settings for windows so help would be nice. thanks.
 
To elaborate (I was on my phone when I responded last night)...The FSB on the current processors is not the way to overclock anymore. It is far less tolerant to overclocking anyway than in the past, and at most you'd be talking a few MHz on the FSB, and probably a much higher risk of instability. It can be useful for people who are really trying to push their machines to be the absolute fastest possible, but for 98% of overclockers, it makes much more sense to just use the multiplier. One thing to note is that the 2500k will generally do auto voltage based on a lookup table in the CPU for each speed...and generally this is set much higher than the chip actually needs to be. Once you find you're stable at the speed you want, see how low you can drop the voltage and maintain stability.

For instance, my 2500K on auto voltage requires about 1.24V at stock speeds. When I first went to 4GHz, it automatically chose 1.30V. However, I've found that I can set a voltage offset of -0.08V and it is still rock solid, so I'm actually running at 4.1GHz and 1.22V...lower than stock. This offset is also enough that my machine is stable at idle, where it throttles back to 1.6GHz and about 0.78V.

You can reset voltage in a few ways...you can set a specific voltage and then monkey with the LLC correction to combat voltage droop, which I don't like to do because it essentially means your chip runs at the full voltage all the time, instead of dropping down at idle. I prefer to use the offset, so that it still uses less power and heat at idle, and should lengthen the life of the chip significantly. It does limit your overclock,though, as once you start climbing to higher speeds, to maintain a safe voltage, you'd need to dial in the offset quite a bit, which would then drop your idle voltage by a huge amount, such that it would start crashing at idle. I know from when I tried set voltage and LLC offset, that my chip will run stably at full load at 4.1GHz and about 1.18V or so, but at that offset (-.12V), I'll likely become unstable at idle.

Still, I'm happy with 4.1 and 1.22V. I'm sure with this chip I could pretty easily go to 4.5GHz and stay at or near 1.3V, but I have no desire at this time (though I might do it towards the end of life for this build). Good luck!
 
thanks much for the extra info. while I have years of computer builds and mods it is in the world of mac. I got tired of macs shift to small mobile gear and constant osx changes. I purchased my first windows pc last year to learn a bit about windows 7. I grabbed a 12 inch asus netbook. I liked the windows 7 os so I decide to build a pc. I have to say it has been pretty straight forward up to now. The build is very quiet and is fast I liked the idea of just a little oc to get to 4.0. Just because you can.

Only need to play with bios a bit more to get lower volts. I set it at 39 it had settings for all 4 cores
34 = 4 oem settings
35 = 3
36 = 2
37 = 1

my settings are
36 = 4
37 = 3
38 = 2
39 = 1

my new temps are 50 c

I am still waiting on more low noise fans to arrive.
 
Yeah, that's a 200MHz overclock. 🙂 When most people say 4 GHz, that's all four cores. Most motherboards have an overall multiplier setting, which can override the turbo...so at 4.1, when turbo kicks in, I get 4.1 whether 1, 2, 3 or all 4 cores are running. If yours doesn't have the main multiplier setting, you can set turbo for all 4 cores to 4.0 GHz (and I'd keep even single core operation at that level when overclocking, as you want to know it's stable...if all 4 cores are stable at a speed, you know one core is stable, but if all 4 cores are stable at 4GHz, one core might NOT be stable at 4.3GHz and the same voltage, which you might not figure out until later.

Is that 50C under full load? If you are getting 50C under full load with 4 prime 95 threads, your cooler is kicking serious butt. If it's 50C idle, that's a different story, and something may be off with the cooler installation.
 
Last edited:
I agree that offset is the way to go, but LLC can be very helpful there as well.

I'm running my 2500k at 4.5 ghz with a -0.04v offset and LLC at 50%.

At idle, I'm supplying 0.976v (VCore) while the CPU is asking for 1.017v (VID). It's rock stable at idle despite the slight droop. Temps around 25-30c idle depending on ambient temp.

Under load, I'm supplying 1.304v while the CPU is asking for 1.346 (and sometimes 1.370). It's rock stable there as well, with temps around 45c under normal load, and around 65c under insane "why would you do this to a CPU" load. Without LLC at 50%, however, I was seeing substantial vdroop (down to around 1.276, creating a difference of 0.07v to 0.1v between VCore and VID) that was causing BSODs under the aforementioned insane load.

Looking at those numbers, you'd think I could just remove the offset (keep offset mode on, but switch the offset to "auto" or 0.00v). But I've left it on for 2 reasons. First, it's saving me teeny tiny amounts of money every month on my electric bill, and who doesn't want to save $0.34 every year by tweaking voltages?! And second, and more importantly, my chip is stable with a significant overclock (3.3 to 4.5) despite being undervolted at idle and load, which will, in theory, increase the longevity of the CPU.

TL;DR, moral of the story, etc: Offset mode is the way to go, but read your motherboard's manual and familiarize yourself with all of the tweaks you've got at your fingertips, including LLC, and you'll find a nice sweet spot for the overclock and voltage that you desire.
 
this looks like a new way to have fun. tweaking bios settings. I am very new at this game just a few hours in. Once I hook up the second intake fan I will get a better temp idea. My case uses very slow fans for noise control so 50c may be normal with the current oc. I am 1 fan short waiting on it to arrive from ups ground.

This machine is a tweener too big for htpc not enough gpu for a gamer.

I have a fanless gpu that gets 7.1 on the windows exper scale. this is another reason for noise. It is fast and it is quiet really quiet. When I setup the system with stock cooler I read 60c but only the intel fan along with the rear exhaust fan. Now I have the evo 212 cooler and the intake fan. with no overclock all standard settings I got 46c .

My case is going to run hotter due to slow fans.

I am going to take this slow as I learn. So all info helps. thanks again.
 
philipma1957 said:
<snip>My case uses very slow fans for noise control so 50c may be normal with the current oc.<snip>
Click to expand...

50c (122f) idle is not normal or OK under just about any circumstances (maybe in Phoenix in July). With an EVO and NO fans, you should be below 50 at idle. Then again, if you have speedstep turned off, or your voltage is set to manual and it's set higher than it should be, your "idle" temps won't be based on typical "idle" settings.

What are you using to measure temps? You should download and install RealTemp 3.70 (for temps and VID -- to display VID, click on the running stopwatch button in the upper right of the program and it will convert to show VID instead) and CPU-Z 1.59 (for VCore, clock speed, and other CPU/motherboard/RAM settings).
 
cytoSiN said:
50c (122f) idle is not normal or OK under just about any circumstances (maybe in Phoenix in July). With an EVO and NO fans, you should be below 50 at idle. Then again, if you have speedstep turned off, or your voltage is set to manual and it's set higher than it should be, your "idle" temps won't be based on typical "idle" settings.

What are you using to measure temps? You should download and install RealTemp 3.70 (for temps and VID -- to display VID, click on the running stopwatch button in the upper right of the program and it will convert to show VID instead) and CPU-Z 1.59 (for VCore, clock speed, and other CPU/motherboard/RAM settings).
Click to expand...

my home is warm 26c or 78 f


I put in second intake fan and over clock is now set to 40 x for each core.

adding second fan my temps moved to 46c.

all fans move very slowly for noise control.


I am using the bios fan reading.

I will download the real temp 3.7 and cpu-z tomorrow.

I will post readings and settings then.

thanks for info. I set mobo back to defalut just in case I was doing something wrong.

my real temps are 31 to 34 per core under 2 % load.

I did prime 95 100% load and my temps were 57 to 59 per core after ten minutes.


this is with oem settings . will try over clock to see changes


okay set the over clock to 36 for 4 cores 37 for 3 cores 38 for 2 cores and 39 for 1 core. seems like this bios only allows for the multipler to do the cores 1 at a time. after 10 miniute of prime 95 my 4 core 3600 over clock reads 63 to 67 degrees. the only settings changed are the multiplers. I have fans in place.

the evo is using 1 fan I may pick a second one up. still at least the idle runs at 31c and even with a 100% load for 15 minutes I am not past 67c on any core. range on the cores 61c to 67c at full load. plus my home temp is 25c
 
Last edited:
philipma1957 said:
still at least the idle runs at 31c and even with a 100% load for 15 minutes I am not past 67c on any core. range on the cores 61c to 67c at full load. plus my home temp is 25c
Click to expand...

That's more like it. We were under the impression that you were running 50c at idle. Also, don't trust the temps in your BIOS. Believe it or not, your CPU is working harder in the BIOS than it will in Windows while idling. Sounds like you should get some nice readings in Realtemp and are well on your way to a stable overclock.

Also, you should apply the same OC to all four cores if you can, as mentioned above.
 
okay I set all cores at 40x . idle is 31c to 35 c at 2% load and at prime 95 max temp was 67 in one core for the high and 61 in the lowest core. after 15 minutes of testing at 100% and a clock of 3.98 I have a question.

my mhz is set at 100mhz which is stock but cpu-z reads 99.8 mhz thus oc is

3.992 I can live with the lack of 4.0 .

do some cpus come a little under or over on the 100 mhz as stock or is it

common?
 
It's not uncommon for your BIOS set BCLK speed to be slightly miscalibrated. Mine is also off by 0.2 MHz. I simply changed my BCLK to 100.2 in my BIOS, which results in a real world speed of 100.0 MHz. It's just nicer that way. 🙂
 
Jman13 said:
It's not uncommon for your BIOS set BCLK speed to be slightly miscalibrated. Mine is also off by 0.2 MHz. I simply changed my BCLK to 100.2 in my BIOS, which results in a real world speed of 100.0 MHz. It's just nicer that way. 🙂
Click to expand...

okay I will check to see if i can do that with my intel mobo.

I am impressed with the quiet quality to the machine.

Also the graphics are very nice on my sony tv via hdmi. Better then any of my current macs. the mac pro with the 5870 card running windows via bootcamp may have had better graphics but cost quite a bit more.
 
Okay my final oc is 41 x 99.8 = 4091.8


it idles at 29c to 31 c and with prime net 95 it reaches 68c to 71c after 25 minutes

I ordered a second fan for the evo 212 the oem model direct from cooler master. After I did research here is a link for the oem model


http://www.cmstore-usa.com/hyper-212-evo-120mm-fan-oem-package/

this is a perfect match .

it should keep the max temps under 70c maybe 65c to 68c. my mobo has a 1.5 amp limit for the cpu fan and this fan is .37 amp x 2 is .74 amp plenty of head room. i grabbed this y cord


http://www.amazon.com/gp/product/B00...00_i00_details


I will get back with the new numbers next week.
 
Those temps are fine, though I'd expect a little better from the 212, as I am typically at around 65-67C during long runs of Prime 95 and I have the smaller CoolerMaster TX3, which should run about 5C hotter than your 212. I do have two fans on it in a p/p configuration, so maybe that's enough to bring them closer in line. Your idle temps are better than mine, though. (I'm at 32C on the low end, more typically 34-36C) Certainly nothing wrong with them. I'd imagine you'll drop 3-4C with a second fan, as I know my temps dropped that much.

One thing to note: your daily actual load temperatures will be much lower than your stress testing numbers. At 4.1 GHz, I hit 72-74C when running Intel Burn Test, mid-high 60s for Prime95. However, when doing something processor intensive in real life, like encoding a movie, I max out at around 60C. During gaming? About 55-56C.

So, expect about 5-10C below your P95 numbers for daily use, and 10-15C below an intel Burn test run.
 
I'm running at 4.2 with idle of 29-34 degrees on my i5-2500k with a hyper 212 evo, so your temps look fine to me.
 
mkmitch said:
I'm running at 4.2 with idle of 29-34 degrees on my i5-2500k with a hyper 212 evo, so your temps look fine to me.
Click to expand...

Agreed. I'm running 4.5 with idle temps around 30 with the non-EVO 212+. But keep in mind that our respective overclocks are irrelevant to idle temps due to speedstep and c1/c3. Basically, at idle, we're all at 1600MHz and under 1.0v. So, in short, your idle temps are fine.
 
you know after 15 years of mac only ownership. owning and building this pc has been a pleasure.

The intel extreme board works pretty well. auto tune is junk but with this site and the intel forum board I got enough info to do a stable oc with manual settings.

The next step is getting the most out of the fanless gpu but that is another part of the forum.
 
Jman13 said:
To elaborate (I was on my phone when I responded last night)...The FSB on the current processors is not the way to overclock anymore. It is far less tolerant to overclocking anyway than in the past, and at most you'd be talking a few MHz on the FSB, and probably a much higher risk of instability. It can be useful for people who are really trying to push their machines to be the absolute fastest possible, but for 98% of overclockers, it makes much more sense to just use the multiplier. One thing to note is that the 2500k will generally do auto voltage based on a lookup table in the CPU for each speed...and generally this is set much higher than the chip actually needs to be. Once you find you're stable at the speed you want, see how low you can drop the voltage and maintain stability.

For instance, my 2500K on auto voltage requires about 1.24V at stock speeds. When I first went to 4GHz, it automatically chose 1.30V. However, I've found that I can set a voltage offset of -0.08V and it is still rock solid, so I'm actually running at 4.1GHz and 1.22V...lower than stock. This offset is also enough that my machine is stable at idle, where it throttles back to 1.6GHz and about 0.78V.

You can reset voltage in a few ways...you can set a specific voltage and then monkey with the LLC correction to combat voltage droop, which I don't like to do because it essentially means your chip runs at the full voltage all the time, instead of dropping down at idle. I prefer to use the offset, so that it still uses less power and heat at idle, and should lengthen the life of the chip significantly. It does limit your overclock,though, as once you start climbing to higher speeds, to maintain a safe voltage, you'd need to dial in the offset quite a bit, which would then drop your idle voltage by a huge amount, such that it would start crashing at idle. I know from when I tried set voltage and LLC offset, that my chip will run stably at full load at 4.1GHz and about 1.18V or so, but at that offset (-.12V), I'll likely become unstable at idle.

Still, I'm happy with 4.1 and 1.22V. I'm sure with this chip I could pretty easily go to 4.5GHz and stay at or near 1.3V, but I have no desire at this time (though I might do it towards the end of life for this build). Good luck!
Click to expand...

Although this may not apply to the OP's platform, the fsb is still used for the 2011 platforms. I use it on my OC, and have had better luck vs. a straight multi change. Just clarifying here...
 
You must log in or register to reply here.

TRENDING THREADS

Back
Top