Stop this BS about the dangers of increased voltage!

KenAF

Senior member
Jan 6, 2002
684
0
0
I took the time to respond to this in another thread, so I might as well do it here too...



<< Read the articles on it...Too high of voltages can cause a term called electromigration and this will kill the chip...Quit telling ppl "if the temps are fine", cause you don't seem to understand the whole picture... >>

If I hear this one more time, I am going to go nuts. This all arose out of a single comment taken out context by Johan at Aceshardware.

Do you people even know what electromigration is? Electromigration is normal; if it weren't for electromigration, processors might last tens or hundreds of years. The danger of electromigration is that the processor will eventually require more voltage to remain at the same speed, and will need to be reduced to a slower speed at the given voltage to remain stable. Eventually, after a substantial period of time, it may stop working completely. However, this isn't something that could occur to a processor overnight, or even over a period of many months. Even at 1.85V on a P4 (assuming reasonable temps), it will probably take years.

Electromigration occurs just from running processors at 100% usage. It occurs when running processor intensive tasks. Some have suggested that electromigration occurs (on the Athlon, not just the P4) whenever the processor temperature exceeds 50C.

Primary electromigration risk occurs from increased temperatures; failure from electromigration increases exponentially with increased temperatures. That said, the copper interconnects in the P4 can carry ten times as much current as aluminum wire, and serve to allow substantially increased temperatures with minimized electromigration risk to the processor. That's part of the reason why Intel moved from aluminum to copper interconnects with the "Northwood" P4--so they could reach higher clocks, and tolerate more heat, while still preserving long-term (essentially indefinite) reliability.

What's a real world example of electromigration? People who overclocked their Celeron 300A @ 581MHz have begun to find, after two to three years, that their processor no longer runs stable at that speed. Some of those who ran their Celeron 300A @ 581MHz for several years now find that it only runs stable at 450MHz or 462MHz. That's due to electromigration. Actual processor failures due to electromigration are very very very rare, considering that few people keep their processors for more than five years.

What is the worst danger one can realistically expect to face from electromigration with the "Northwood" P4? Well, if you don't have good cooling, you may find in three years that your P4 1.6A will no longer run stable at 2560MHz. Instead, you may have to clock it down to 2400MHz. Big deal. The chance of a P4 processor, with increased voltage and adequate cooling, completely failing in several years is about as close to 0% as you can get.
 

XRaider

Senior member
Mar 1, 2001
226
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0
Yea.. how you like them apples! -sorry it's friday and it's nice as heck outside and I'm couped up in this hell hole with flourecent lighting.
BTW - Good info, thanks!
 

LarryJoe

Platinum Member
Oct 22, 1999
2,425
0
0
KenAF - I hope you don't mind, but I posted this over at the Abit section of the overclockers.com forums. It is too well written and informative to not share. Of course I gave you the credit Thanks for taking the time to set people straight.
 

jiffylube1024

Diamond Member
Feb 17, 2002
7,430
0
71
Good stuff Ken! I've read a lot of your posts/replies, and I respect your opinions. This was an excellent post, and definately a necessary one here @ AT to shut everyone up about this issue (although it could be the cause of even more debate).

Either way, great post; keep up the good work! Btw, it's right on the money about how people say "dont increase the voltage", "don't overclock" when a higher clocked CPU is taking less damage than one running @ 100% load constantly!
 

Mikewarrior2

Diamond Member
Oct 20, 1999
7,132
0
0
Nice post KenAF,

One note though... INcreasing voltage is one of the major proponents of increased heat.... Voltage increases raise heat more than mhz increases in most instances.

For example: an XP1600+ chip at 1400mhz, default voltage puts out 62W. The same chip, at 1400mhz, 2.1V would put out 89W. With the average heatsink C/W of .4, the extra 27W would mean a CPU temp increase of ~10.8C. (didn't have p4 northwood calc handy, so I used the amd power calc).

Of course, this isn't meant to take away from your informative post about EM and its dangers as well as urban "internet" myths regarding it. Just food for thought, for the person thinking about extreme overvolting.....



Mike
 

Torval

Member
Jul 10, 2001
79
0
66
damn, this post has been around for 5 hours, and not one flame!! amazing..

thanks for the info....I have been trying to keep my 1.6a under 1.6 on the core voltage,
but not I think I will be a little more brave.
 

LarryJoe

Platinum Member
Oct 22, 1999
2,425
0
0
Just wait til the kids get home from school j/k

I think it is noted that overvolting produces heat and good cooling is needed. Extreme overvolting requires extreme cooling, etc.

 

boyRacer

Lifer
Oct 1, 2001
18,569
0
0
Ahhhh... that explains it... Can it happen within a month at least? My old p3 1ghz @ 1.33 (same speed as the one im running now)required only 1.95v to run everything stable... then once in awhile it would give me a BSOD... so i bumped it up to 2.00v and no BSODs for about a week... and then playing games would make it crash... if i put it to 2.05-2.1v it was stable again... but the temps were getting too high for me @ 52c load... so i switched it with my spare. This one is running at 2.0v @ 45c load with no problems for about two weeks now. Do you think thats what happened?
 

BadThad

Lifer
Feb 22, 2000
12,095
47
91
ahhhhh....the rare intelligent post! Nice one man.

I hear you, the amount of mis-information found in forums makes me crazy too. I really like the one where people tell others to defrag their hard drive to free more space...HAHAHAHAHA.
 

Richardito

Golden Member
Feb 24, 2001
1,411
0
0


<< ahhhhh....the rare intelligent post! Nice one man.

I hear you, the amount of mis-information found in forums makes me crazy too. I really like the one where people tell others to defrag their hard drive to free more space...HAHAHAHAHA.
>>


Yeah, there's people that are just ignorant and others that are pimping a product (like AS).
 

MilkPowderR

Banned
Mar 30, 2001
529
0
0


<< Ahhhh... that explains it... Can it happen within a month at least? My old p3 1ghz @ 1.33 (same speed as the one im running now)required only 1.95v to run everything stable... then once in awhile it would give me a BSOD... so i bumped it up to 2.00v and no BSODs for about a week... and then playing games would make it crash... if i put it to 2.05-2.1v it was stable again... but the temps were getting too high for me @ 52c load... so i switched it with my spare. This one is running at 2.0v @ 45c load with no problems for about two weeks now. Do you think thats what happened? >>


To answer your last question, hell no. hehe.. no offense, just kidding
I believe your cD0 P3 1Ghz processor is a lillly-bit dud one. Yours wanting more voltage to run happily@ 1.33. Yours isn't causing electromigration. You've been using it for 5'ish months. You may not have found the exact amount of voltage you need to up it to make it completely stable. It seems 2.10V is most stable for u.


To Ken,
There are few things I wanted to quote you and wanted to brag you. So damn awesome..


<< Primary electromigration risk occurs from increased temperatures; failure from electromigration increases exponentially with increased temperatures. That said, the copper interconnects in the P4 can carry ten times as much current as aluminum wire, and serve to allow substantially increased temperatures with minimized electromigration risk to the processor. That's part of the reason why Intel moved from aluminum to copper interconnects with the "Northwood" P4--so they could reach higher clocks, and tolerate more heat, while still preserving long-term (essentially indefinite) reliability. >>


That was very very very good explanation and I am damn glad you brought it out. Lately, even with these new chips, many people think upping the voltage is still a quick way to kill their P4 Woodie's and Tualatin version of P3-S/Celeron chips. Many of them don't realize what the hell is in the chip. People have forgotten that the Coppermine chips have Aluminum interconnects whereas the Tualatin and P4 Woodie chips have "Copper" interconnects. Copper handles heat a lot higher than the Aluminum. It's proven fact. Ol'man has good explanation to this matter.



<< The chance of a P4 processor, with increased voltage and adequate cooling, completely failing in several years is about as close to 0% as you can get. >>


I am touched..... That was so good phrase. Well said, Ken.



 

alkaprim

Member
Jul 15, 2001
38
0
0
I'm not expert on quantum phisics but with 0.13micron gate wouldn't you get barrier of approx ~1000 athoms?
Probability of quantum tunneling is not a linear function.
So going from 1500 athoms to 1000 may increase probability more than simple interpolation .
 

mschell

Senior member
Oct 9, 1999
897
0
0


<< Primary electromigration risk occurs from increased temperatures >>



I think you should explain what "increased temperatures" actually are.
Is it 10F over a nominal 120F operating temperature?
What is "good cooling"?
Does it mean a CPU with cryo cooling will last forever?

Here's something else that should be answered while you?re at it.
What is the average lifespan of a CPU anyway?

Why does Intel spec the Northwood for 1.5v when they can simply spec them for 1.7v and get much higher yields which equals more money for them?

The answer is overvolting a CPU or other complex IC reduces its effective life span. By how much I don't know, as one needs to know the answer to question 3 above. This reduction has very little relevance to people here as most don't keep a CPU for more than a few years at the most.
When it comes to heat and electronic IC's you should know that many devices function perfectly fine in temps of 140F - 160F and they last quite a long time also so I don't think heat in itself is a killer of CPU's.
Because Intel and other CPU makers can't wait 5 or 10 years to give actual life cycle testing to CPU's, they do it virtually using accelerated computer simulations. This lets them know that x amount of voltage applied will allow a CPU to last X amount of years among other things.

As to the "dangers" of increased voltage. The only danger I can see is having to replace your $150 processor when you overclock it too much. Real chicken feed compared to adding a bit to much boost or timing to an automotive setup and destroying a $3500 motor.
Be happy that you can play close to the edge for so little $$


 

rogue1979

Diamond Member
Mar 14, 2001
3,062
0
0
I love to play games on my Athlon rig. In it's current configuration at 1.98v I hit a max cpu temp (prime95 for 2 hours) of 46c, and that's without a Delta, thank god. Most of the time I spend surfing on the web, and I would cringe at the thought of running 46c all the time. My board has an AMD 761 chipset and I simply use Wpcrset. My cpu temps when surfing or doing light desktop work stay at ambient, that's about 25c. I feel if one takes extra cooling precautions then the overclocked cpu probably runs cooler than a stock system running stock speed anyway.
 

jiffylube1024

Diamond Member
Feb 17, 2002
7,430
0
71


<< Ahhhh... that explains it... Can it happen within a month at least? My old p3 1ghz @ 1.33 (same speed as the one im running now)required only 1.95v to run everything stable... then once in awhile it would give me a BSOD... so i bumped it up to 2.00v and no BSODs for about a week... and then playing games would make it crash... if i put it to 2.05-2.1v it was stable again... but the temps were getting too high for me @ 52c load... so i switched it with my spare. This one is running at 2.0v @ 45c load with no problems for about two weeks now. Do you think thats what happened? >>



Old P3's (pre-tualatin) were not good overclockers over 1 GHz. Remember that whole scandal about 1.13 GHz not working stably. They just didn't have the yields on above 1 GHz CPU's back then. I'm amazed you got it to 1.33 GHz



<< Why does Intel spec the Northwood for 1.5v when they can simply spec them for 1.7v and get much higher yields which equals more money for them? >>



Because they CAN. Why would intel run all their CPU's at the higher 1.7 voltage when they know they will run stably at lower voltages. Since they CPU's can run stably @ 1.5 V (obviously... I mean you can overclock northwoods 200+ MHz at stock speed) why would they increase the default voltage unnecessarily. They set the voltage to the minimum stable level. Also they always lower the core voltage after a die shrink.

Another point: all of these overclockers running P4's @ high voltages are EXACTLY WHAT INTEL NEEDS. We are like beta testers of the new P4's at high voltages. Since running a P4 @ 1.6 V or even 1.7V with slightly better than their current retail cooling is (apparently) not harming the chip whatsoever, Intel knows that they can increase the default voltage down the road safely. What this means is that, along with better yields, the P4 will hit 3 GHz easily very soon (less than 6 months) and most probably 4 GHz within a year or so at a slightly higher voltage.
 

Def

Senior member
Jan 7, 2001
765
0
0
Intel is a multi-billion dollar corporation. Why the hell would they rely on questionable data attained from an overclocking forum? They can just run a few hundred chips at higher voltage and find out themselves. It's not like they're hard to get, they do produce them afterall.

Of course, they've already done this, hence why they have a spec sheet stating the maximum operating voltage. I'm not sure what it is for a Northwood, but it is more of a suggestion than an omen. If you exceed this voltage by 0.05V or even 0.10V I'm sure your chip will last decades with retail cooling.




As for the original topic, I'm sure some person stated a voltage they thought was safe. Then through the wonders of the internet, it was turned into an unwritten Overclocker's Law that ye shall not exceed this value or risk penalties from the Great Overclocking Gods.

Of course, that's just my opinion. I could be wrong.

Defster
 

Migroo

Diamond Member
Jul 14, 2001
4,488
9
81


<< What is the worst danger one can realistically expect to face from electromigration with the "Northwood" P4? Well, if you don't have good cooling, you may find in three years that your P4 1.6A will no longer run stable at 2560MHz. Instead, you may have to clock it down to 2400MHz. Big deal. The chance of a P4 processor, with increased voltage and adequate cooling, completely failing in several years is about as close to 0% as you can get. >>



The point should be that in 3 years the difference between 2400 or 2560 MHz will be F**K all... (to put it technically)

Great post KenAF.
 
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