Do I really need to go from 3.6-4.0?

Dangman

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70c still scares me. And isn't 1.7v dangerously high? Don't you get some kind of voltage migration or something like that that can slowly fry your chip?
Yes. 1.7v on a 65nm Core 2 without some form of water or sub-zero cooling is definitely not a good idea for continuous operation.
Even if I water cool, isn't that still bad? Say I put an uber watercooling system that keeps it at below 50c even at highest 4 core load ... doesn't just the sheer amount of voltage possibly damage the chip?
Yeah, probably. I wouldn't do it under any circumstances to be honest, unless it was a disposable chip.
Yes 1.7V is way too high for any C2D derived CPU. 1.5V is the max recommended voltage for 65nm C2D CPUs and 1.4V max for 45nm C2D CPUs.

Luckily SirKronan was on the ball and didn't leave his OC at that voltage.
 

vengence

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Yes 1.7V is way too high for any C2D derived CPU. 1.5V is the max recommended voltage for 65nm C2D CPUs and 1.4V max for 45nm C2D CPUs.
IIRC, Intel's spec limit is 1.35Volts, is 1.5 the "accepted safe limit"?
 

Zero82z

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Your E8400 is a 45nm CPU. Don't go over 1.4v. If you had a 65nm CPU, you would need to stay under 1.5v.
 

vengence

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Your E8400 is a 45nm CPU. Don't go over 1.4v. If you had a 65nm CPU, you would need to stay under 1.5v.
Yeah, I read that earlier pretty quickly (on a 5 min bathroom break from a meeting to be specific ;)) and somehow got that a E8400 would be fine up to 1.5volts and someone had run one at 1.7 without releasing the magic smoke.
 

SirKronan

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Yeah, I read that earlier pretty quickly (on a 5 min bathroom break from a meeting to be specific ;)) and somehow got that a E8400 would be fine up to 1.5volts and someone had run one at 1.7 without releasing the magic smoke.
I FOUND IT!!! I knew that there was something else that can damage your CPU with overvolting, and even more so on 45nm. That's why 45nm has a 1.4v limit whereas a 65nm has a 1.5v reasonable overvoltage limit. HEAT might not be the problem at all:

"Electromigration is the transport of material caused by the gradual movement of the ions in a conductor due to the momentum transfer between conducting electrons and diffusing metal atoms. The effect is important in applications where high direct current densities are used, such as in microelectronics and related structures. As the structure size in electronics such as integrated circuits (ICs) decreases, the practical significance of this effect increases."

With a 45nm CPU there is less distance for the electronic signal to travel. This is part of the reason why they are cooler and more efficient. Less circuit between point A and point B equals more efficient signal transfer, less resistance, and less time (when we're talking nanometers the time is not a huge difference.) The logical reason, at least in my mind, why a 65nm can take more current safely than a 45nm is because it's larger, and that distance is greater - however the 65nm produces more heat and is a less-efficient design. Hence, the 45nm will do what a 65nm will do with less required voltage."As the structure size in electronics such as integrated circuits (ICs) decreases, the practical significance of this effect increases."

Does that make more sense now, vengeance?? Even if you watercool or subzero cool, electromigration is still going to shorten the lifespan of your processor, possibly significantly. At 1.5v I am safe, but at 1.7v, even with my TRUE keeping the temps down around 70c, I am damaging my processor by shoveling a lot more electricity into it than it was designed to handle. 1.5v for the most part is pretty safe on Core 2 Duos with 65nm. But with 45nm, keep those volts down. Even if I use dry ice and my 45nm processor (i don't actually have one yet....) never goes above 25c, 1.7v on it is going to cause some considerable electromigration, and the processor is going to wear out much faster.

Remember Intel's design methodology, as well. A Core 2 quad is just two Core 2 Duos on the same die, pretty much, so the same 1.5v limit applies, just with a lot more heat being put out because there's two on the same chip in roughly the same amount of space and with the same area of contact to dissipate heat. Partly why quads are so much more demanding on motherboards to overclock, even if you have amazing cooling.
 

Matthew Kane

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Yes. 1.7v on a 65nm Core 2 without some form of water or sub-zero cooling is definitely not a good idea for continuous operation.
Supposedly you do use some kind of extreme cooling method. Once you reach that kind of power increase...the components around your motherboard CPU area will degrade and if so, after a restart can leave your motherboard dead just like that!


About the 70'C thing...Before my Pentium D 915 died, I had it stock, overclocked to 4.8GHZ with 1.45v running through it from the stock 1.325v (In attempt to reach a 5GHZ record for myself!:p. The temperatures was at 60 load and 38 Idle on Air using a Thermaltake Big Typhoon 12 cooler. The max temp from the Intel Spreadsheet was what?...95'C max before death kicks in and the cpu will stop functioning. Guess what.....because I thought I had it at low 60's I thought that it never will reach past 65'C. During the summer breaks...as my usual routine of video converting...reading from Speedfan gave a temp of 80 under load after a quick trip to the toilet....5 minutes later....restarted my computer to lower the overclock....my computer wouldn't turn on again.....I retested both the cpu and motherboard....guess what? It was all dead. Intel said that you can't go pass 95'C of what ever it was, speedfan only recorded 80 or so degrees celcius.....but why did it die? Dunno....just proves that if doesn't need to reach that point to fuk up....it can happen when ever whatsoever!:(
 

Matthew Kane

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Some OEM systems with Q6600's run stock in the 80's due to lack of airflow in the case, and they run perfectly fine.

That is not true...unless it was a Dell or the PMW cable was disconnected somehow!

They will run a little hot then most due to the lack of airflow for some, but the temp won't reach that high whatsoever!
 

Zero82z

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Supposedly you do use some kind of extreme cooling method. Once you reach that kind of power increase...the components around your motherboard CPU area will degrade and if so, after a restart can leave your motherboard dead just like that!
If you cool down the components enough, it is possible to greatly reduce degradation. That is how extreme overclockers are able to reach high speeds. However, sub-ambient cooling is generally a minimum requirement for such activities.
 

Riccochet

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That is not true...unless it was a Dell
You realize you just contradicted yourself?

Shovel a Q6600 into a SFF case from HP, or whoever, give it 1 case fan and see what happens. Have you not seen a stock Q6600 load in the mid to upper 60's in a well ventilated case with the stock cooler? I have. There are umpteen threads here to support that as well.
 

vengence

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Electromigration <snip>
I am aware of electron migration. It is very similar (at least to think about) to fatigue in metals. I am not aware how much it is a problem.

Over volting is dangerous. That's the long and the short of it. You will shorten the life of your CPU even if properly cooled. Now if you figure your only going to keep your CPU for a year, and you can afford to replace it if it dies, then by all means have some fun. I've been tempted to get to 4.5 on air on the system below. I don't think I'd run it at that though. You can also damage your motherboard as well as your probably going to be increasing other volatges too.

But, if you can afford to fix it when you break it, go have fun. If you've got a wife and a kid, then I'd advise against you commiting sucide by wife. :p
 

imzjustplayin

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I am aware of electron migration. It is very similar (at least to think about) to fatigue in metals. I am not aware how much it is a problem.

Over volting is dangerous. That's the long and the short of it. You will shorten the life of your CPU even if properly cooled. Now if you figure your only going to keep your CPU for a year, and you can afford to replace it if it dies, then by all means have some fun. I've been tempted to get to 4.5 on air on the system below. I don't think I'd run it at that though. You can also damage your motherboard as well as your probably going to be increasing other volatges too.

But, if you can afford to fix it when you break it, go have fun. If you've got a wife and a kid, then I'd advise against you commiting sucide by wife. :p
Well another thing he should be aware of is that electromigration is sped up with higher temperatures which is WHY people sometimes undervolt their systems and put beefier cooling systems on there. Make the chips run really cool and lowest necessary voltage and they'll last far longer, the question is, how long do you really need it to last anyhow?
 

Riccochet

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The last processor I had that started flaking out on me was an 8088 back in the 80's. Unless you're doing something wrong or completely out of spec for the processor it should last at least 3 years till it's power is no longer useful for newer software. Even then I'd say 99% of CPU failures are PEBKAC issues.
 

vengence

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the question is, how long do you really need it to last anyhow?
yep, that's kind of it for me. I'm not going to be using this chip in 2 years. I don't even think my wife will still have it as a "hand me down" in 2 years.
 

Brahmzy

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The simple answer: yes.

I went from an E8400 @ 4.0GHz to an E8600 @ 4.4GHz and it's great. I don't think I can tell a lick of difference, but that's not the point.
 

imzjustplayin

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yep, that's kind of it for me. I'm not going to be using this chip in 2 years. I don't even think my wife will still have it as a "hand me down" in 2 years.
But you could always sell it. I'm still using pentium pros so I don't see why you have to destroy this chip unless you've got a good reason. If you were video encoding and need the fastest speeds, I'd understand but otherwise I don't see the point. I'd prersonally would be more interested in recouping my costs than anything else.
 

SirKronan

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But you could always sell it. I'm still using pentium pros so I don't see why you have to destroy this chip unless you've got a good reason. If you were video encoding and need the fastest speeds, I'd understand but otherwise I don't see the point. I'd prersonally would be more interested in recouping my costs than anything else.
That's why I switched from my 780i to the new P45. I decided that quad overclockability and overall platform stability were more important to me than triple SLI. My system still games mean and lean with a 4850 (will add a second later as games demand more). But my processor is so much cooler and more stable, even at 3.6GHz, on the P45 platform. And the board was less than half the cost. I definitely notice a difference video encoding, and in some games like supreme commander too. Totally worth it to go from 3.0GHz to 3.6GHz, especially on a quad. Photoshop, pinnacle studio, & multitasking LOVE my new P45-based system.
 

Matthew Kane

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You realize you just contradicted yourself?

Shovel a Q6600 into a SFF case from HP, or whoever, give it 1 case fan and see what happens. Have you not seen a stock Q6600 load in the mid to upper 60's in a well ventilated case with the stock cooler? I have. There are umpteen threads here to support that as well.
First of all, out of all the OEM suppliers, Dell is about the only that has had a long record of history for their inqdequete cooling in their cases (I mean their LGA775 HSF is totally different and a 12cm fan running at 600-900 rpm and they have no case fans) I own a HP and I know what its like, and I do know that it is a mATX and its cramped and a pretty bad design that has gone into it, but the original Pentium D 935 processor that came with it was only running 38-39 IDLE and LOAD was mild 50's along with a stock AVC HSF that HP supplied it with and also a 90mm back case fan. Pentium D's run about the same heat output and power consumption as C2Q's, no probably even more. You mentioned that Q6600's mid to upper 60's on LOAD??! Thats pretty stupid get a mATX Antec P190 like case and with stock cooler and everything on stock...tell me if that loads up to mid 60's. And if your answer is no then your pretty stupid yourself..because all stock Intel Coolers LOAD up to around mid 60's (unless you had a tweak to your cooling creating some kind of wind tunnel going effectively through the curved fins of the cooler) , hence thats why stock OEM machines load up to those temps as well!
 
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