Need help on CPU cooler

[muddocktor]

I'm talking about an everyday clock that's stable, versus a very high, benching team type overclock that is just stable enough to finish running a particular bench well enough to get a screencap of the score.

Take my 2500k for example: it's running at 4725 with about 1.31v vcore and is totally stable and actually I leave it running there while offshore at work while running Rosetta@Home under BOINC. That keeps it loaded at 100% processor usage and temps run in the low 60's with a copper TRUE installed. Now I haven't really tried looking for the max overclock on it, but I did start seeing a sharp ramp up in vcore for stability at around 4.6. I probably could get to 4.9-5.0 with it, but with vcores up where I wouldn't be comfortable running at all the time. But what I find uncomfortable for a vcore might be acceptable for you. With a 32 nm proc, I don't feel comfortable with a vcore exceeding 1.4v for a 24/7 clock. But then, since I run multiple machines doing Rosetta, I can't afford to kill a proc in a year or less by electromigration either; it would kill my wallet.

 

[nubki11a]

Thanks I won't really increase my voltages, they do reduce the lifespan of your CPU a bit right? Anyway, 4.7 would be just fine for me, thanks a lot for your explanations About the 32nm proc, u mean that I could get a bigger proc that will OC better? Or are all the 2500k's the same.

 

[muddocktor]

They are all the same. I was referring to the process that the 2500k is made on. Intel first rolled out the 32nm process with the 980X LGA1366 and Clarksdale LGA1156 processors and all the LGA1155 processor to date are built on the same 32 nm process. The upcoming Ivy Bridge processors next year will be based on a new, smaller 22 nm process but are supposed to be pin compatible with present 1155 boards with a bios update.

 

[nubki11a]

Alright, but what did you mean with that you wouldn't try OCing any higher on a 32m chip? Were you referring to the Ivy Bridge, that you would with the IB (increasing the voltages).

 

[muddocktor]

It's not so much the overclock per se, but rather the vcore you will need to get there. Heat kills a proc, no doubt, as well as running elevated core voltage, especially over long term use. Keeping the temps down by using a premium cooler will help offset degradation and also will allow higher vcore to be used without excessive temps. Plus, it also depends on your inidivdual processor and what it needs to run at a particular speed. Say you got a cherry 2500k; you might be able to get to 4.8 or 4.9 with a vcore under 1.35v. You could run that particular processor at a higher overclock than mine and still keep long term reliability. Or conversely, you could have a processor that needs 1.4v or higher vcore just to run at 4.5 or 4.6. In that case, your overclock will most probably be lower than mine. It all depends on what your processor clocks like and don't think that a 5 GHz 2500K for 24/7 usage is the norm. Also, as you add vcore to the processor, your thermal load jumps wildly higher as compared to a simple speed increase. Your 2500k is a 95 watt TDP rated processor at it's stock speeds. And as you bump up the speed, but without a corresponding vcore increase, the TDP will go up in a pretty linear fashion. But once you start adding more vcore to the equation, the watts dissipated jump way up.

Let me give you an example: On this page there is an overclocked wattage calculator and we'll use my 2500k as the example. I need 1.312v vcore for a 4.7 overclock. Using their stock settings for a 2500k in the calculator, it shows 1.3v as the stock vcore which is total BS for my 2500k, which is around 1.2v or less and I am using 1.2v vcore for the baseline vcore. Anyways, plugging in my overclock of 4725 and my overclocked vcore at 1.312v, my TDP is now up to 162 watts. But say I needed 1.45v vcore to get the same overclock. Plugging that in, my overclocked wattage jumps up to 198 watts for the same speed overclock. And with the higher wattage also comes a harder time to cool the processor down too. Say I wanted to run my 2500k at 5.0 instead of 4.7, but to do this it took a vcore of 1.55v (this is totally hypothetical as I haven't seen what this 2500k tops at). At that overclock and vcore, my processor is now using 240 watts and that is a very healthy heatload to try to cool on air. Not impossible, but it's much harder to cool than the 4.7 overclock. And actually these Sandy Bridge procs are easier to cool than my i7 930 in my heatsink test rig.

I hope this helps you out what I am trying to explain to you.

 

[nubki11a]

Wow. Thanks so much for making an effort to explain it to me That was a great explanation and I understand it now So basically, as long as you dont have to increase the voltage, the you kan keep putting up a higher clock speed without getting too crazy temperatures. Because when you increase the voltage, the watts increase, increasing heat reducing proc lifetime. Fascinating how it all works Thanks a lot again for taking the time to explain it to me thank.

 

[grumperfish]

^^^
Realistically you can continue increasing core speed as long as voltage remains at 1.38V or lower (for CPU longevity), and your core temps stay below 72C (barring prime95 or IBT when they can get to ~80C for short testing periods).

Let me give you an example: On this page there is an overclocked wattage calculator and we'll use my 2500k as the example.

Thanks for the link. According to this, my 2600K overclock is running at 271W, which is pretty close to the figures I'm seeing in HWiNFO64 with max IBT. It would be a bit lower, however this chip likes volts. My 920 at 4ghz was touching 300W so this one is slightly cooler at a much higher overclock not even taking IPC increases into account.

Either way, this Thermalright cooler does a nifty job of keeping temperatures in check. Played 5 hours of Space Marine the other day before I realized that my fans were still at 7V, and core temps stayed around mid-50C.

 

[nubki11a]

Ok, well I wont be OCing yet as I dont have the pc yet but it is relatively easy right?

 

[grumperfish]

Ok, well I wont be OCing yet as I dont have the pc yet but it is relatively easy right?

Go into BIOS, set CPU multiplier to 42, save settings, reboot at 4.2ghz.
Yeah it's pretty easy now, especially for basic overclocks like that.

If you go above 4.3ghz you'll have to do a bit more work: Testing voltages and overclocking for each multiplier step with IntelBurnTest (with the LINPACK binaries from Intel's site)/Prime95. Most of the voltages don't need to be messed with, and Sandybridge doesn't have separate multipliers for uncore/QPI like the older boards which makes things pretty easy. You can manually change the BCLK in BIOS, but you should keep BCLK on either AUTO or 100mhz, as changing it can do very bad things to your PC. LLC can be set in low to moderate steps, and you can use it while overclocking to keep your vcore voltage down.


The most I've done for 4.6ghz was setting offset voltages (to keep C-States & EIST power-saving enabled), manually setting PLL voltage to 1.75V, manually setting the RAM voltage to 1.52V & setting RAM timings (for extra stability with 4 RAM slots filled), and bumping up VTT voltage slightly, as my board likes to overclock VTT too far when it's left on auto. Everything else is left on auto really.

It probably sounds a little complicated, but it's really not at all difficult to overclock these chips. The hardest part is testing to make sure the overclock is stable within the acceptable temperature and voltage envelope (see my post above). IntelBurnTest makes the testing steps go by alot quicker than Prime95. You're not going to find too many recent guides on Sandybridge overclocking (some older ones suggest BCLK overclocking, which you SHOULD NOT DO -> stick to multiplier overclocking instead), as if you're not really pushing the envelope, it's just that easy.

 

[nubki11a]

Thanks for your help guys I guess I can just follow a guide when it comes to overclocking and I'll be fine? Thanks again

 

[grumperfish]

Thanks for your help guys I guess I can just follow a guide when it comes to overclocking and I'll be fine? Thanks again

If you need to, sure. Just ignore anything regarding BCLK overclocking. Keep it at 100mhz.

 

[pinkfloyd48]

Just get a Antec Kuhler 620 and you will be happy nice and quiet Ihave it on my 1100t on Sabertooth990FX oc a little and it runs 22c at idle and 45c on OCCT for hour and its cheap it replaced my Zalman 9900

 

[Conumdrum]

Just get a Antec Kuhler 620 and you will be happy nice and quiet Ihave it on my 1100t on Sabertooth990FX oc a little and it runs 22c at idle and 45c on OCCT for hour and its cheap it replaced my Zalman 9900

If you followed the thread you would see he already has a new cooler.