Sandy Bridge Overclocking

[DJDeCiBeL]

I'm just interested to know which multiplier most people use to OC on SB and to see what everyone's opinion is on doing it the way the do. If you think one way is better than the other, feel free to say why.

 

[DJDeCiBeL]

There is only one multi.......

Only one for the CPU, in general, yes, but as you know, there are two different ways to change it and different reasons for doing so, so that's what I'm asking here...

 

[DJDeCiBeL]

Well i am stumped.
There is only one way to change my multi....

I'm guessing you have Turbo disabled. If you do, using the Turbo multipliers won't be an option.

 

[robertris2]

I up my turbo multiplier for ocing. First of all its easy, and at my modest 4.5 oc I don't see the need for anything else. Although for sandy bridge I do believe turbo is the only multiplier.

 

[Deleted member 217926]

Well i am stumped.
There is only one way to change my multi....

You don't seriously have your 2500K at 5Ghz and 1.48v do you? If so enjoy the few months your chip will last. If your lucky. Either way get that crap off your sig. People who can't afford a new CPU every few weeks might think those are safe settings.

I have Turbo disabled in my chip and the overall mulitplier at 45.

 

[robertris2]

You don't seriously have your 2500K at 5Ghz and 1.48v do you? If so enjoy the few months your chip will last. If your lucky. Either way get that crap off your sig. People who can't afford a new CPU every few weeks might think those are safe settings.

I have Turbo disabled in my chip and the overall mulitplier at 45.

Hmm, I must have missed something, I thought turbo was the only multiplier. How did you do this? Good I'm noob

 

[Deleted member 217926]

Just disable Turbo in BIOS. You can overclock Sandy Bridge chips several ways. You can overclock via the Turbo by raising the max clockspeed the individual cores will upclock to under load or you can overclock via the CPU multiplier. I just overclocked via the multiplier by raising it from 34 to 45. I left all power savings features on so the chip downclocks when it does not need the power. The difference is that when using Turbo the CPU still upclocks a single core at a time as needed just to whatever higher multiplier you have set. When overclocking with Turbo off the CPU is either at max speed or downclocked due to power savings.

 

[robertris2]

Just disable Turbo in BIOS. You can overclock Sandy Bridge chips several ways. You can overclock via the Turbo by raising the max clockspeed the individual cores will upclock to under load or you can overclock via the CPU multiplier. I just overclocked via the multiplier by raising it from 34 to 45. I left all power savings features on so the chip downclocks when it does not need the power. The difference is that when using Turbo the CPU still upclocks a single core at a time as needed just to whatever higher multiplier you have set. When overclocking with Turbo off the CPU is either at max speed or downclocked due to power savings.

I set my turbo to change all cores, there is the option to do it per core, or by all cores. At least in my mobo I do not see a option to change a normal multiplier, only turbo.

 

[Deleted member 217926]

Never heard anyone having a dead cpu from it...
Proof or it never happened.

Simple physics and electromigration. Anything approaching 1.4v starts to severly limit CPU life. Anything over 1.4v and you start to see CPUs last weeks not months. Why do you think 99% of the people here on Tom's have ~4.5Ghz overclocks? Not only is that speed pretty much the chips scaling limit with very few things actually benefiting from higher clocks but it keeps the CPU's voltage and temps in a safe range. With a very good custom water loop you can get away with 5Ghz daily clocks.

http://www.tomshardware.com/reviews/automatic-overclock-motherboard-cpu,3048.html

From Tom's test labs.

" We've learned through trial, error, and dead processors that voltage levels beyond 1.45 V at above-ambient temperatures can kill an Intel CPU etched at 32 nm (Sandy Bridge-based parts included) very quickly. Those same processors die a fairly slow death at voltage levels between 1.40 V and 1.45 V (somewhere between weeks and months on our test benches). And we're expecting more than a year of reliable service from the parts we've dutifully kept below 1.40 V. Not all motherboards are perfect however. Voltage instability on a particularly cheap motherboard fried one of our processors when it was set to only 1.38 V. Subsequently, you've seen us use 1.35 V for the overclocking tests in older motherboard round-ups, embracing 1.38 V to 1.40 V in more recent pieces covering higher-end platforms. "


Since I can't afford a new CPU ever few weeks to months I am quite happy with my 4.5Ghz 1.32v overclock.

 

[robertris2]

Simple physics and electromigration. Anything approaching 1.4v starts to severly limit CPU life. Anything over 1.4v and you start to see CPUs last weeks not months. Why do you think 99% of the people here on Tom's have ~4.5Ghz overclocks? Not only is that speed pretty much the chips scaling limit with very few things actually benefiting from higher clocks but it keeps the CPU's voltage and temps in a safe range. With a very good custom water loop you can get away with 5Ghz daily clocks.

http://www.tomshardware.com/reviews/automatic-overclock-motherboard-cpu,3048.html

From Tom's test labs.

" We've learned through trial, error, and dead processors that voltage levels beyond 1.45 V at above-ambient temperatures can kill an Intel CPU etched at 32 nm (Sandy Bridge-based parts included) very quickly. Those same processors die a fairly slow death at voltage levels between 1.40 V and 1.45 V (somewhere between weeks and months on our test benches). And we're expecting more than a year of reliable service from the parts we've dutifully kept below 1.40 V. Not all motherboards are perfect however. Voltage instability on a particularly cheap motherboard fried one of our processors when it was set to only 1.38 V. Subsequently, you've seen us use 1.35 V for the overclocking tests in older motherboard round-ups, embracing 1.38 V to 1.40 V in more recent pieces covering higher-end platforms. "


Since I can't afford a new CPU ever few weeks to months I am quite happy with my 4.5Ghz 1.32v overclock.

Nice bit of info here. I guess I'm lucky to have my 4.5 @ 1.3v stable.

 

[Deleted member 217926]

As the manufacturing processes get smaller the more voltage will be a concern. Just check out how bad Ivy Bridge hates volts.

http://www.anandtech.com/show/5763/undervolting-and-overclocking-on-ivy-bridge

 

[Deleted member 217926]

Obviously you don't understand anything if you are going to compare a Phenom to Sandy Bridge. The H100 is NOT a good custom water loop and is about equal to or a tiny bit better than good air cooling. I stand by the physics I know. You are risking the lifespan of your CPU due to electromigration.

The MAX voltage for a Sandy Bridge chip is 1.52v correct. Nothing safe about it. But by all means ignore me and the test labs at Tom's. Just remember that voltage is a measure of force. What you are basically doing is running 100 gallons of water a minute through a hose that is rated for 75 gallons per minute. It's going to case stretching and leaks. You can just tape up a hose that does that.....not so much your CPU.

 

[yummerzzz]

I've seen i5-2500K's at 1.48V fine before.....

I don' know what the fuss is all about, the CPU will last more than enough time.