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Why does More voltage=better OC.
- Thread starter bigal40
- Start date
ssvegeta1010
Platinum Member
Yes more voltage makes more heat, but it also helps to power the components moving at a higher than stock speed. (because speed higher than stock sometimes needs voltage higher than stock to run properly)
MisterChief
Banned
Usually, CPU's are rated at a speed deemed "safe" by the manufacturer. The speed on the box usually isn't the best speed that core can attain. It's just because the CPU will last longer than a CPU with higher voltage. It's perfectly fine to OC a processor, as long as you know what your doin, or someone who knows does it for you. Just make sure you have sufficient cooling!
GuitarDaddy
Lifer
I don't know the technical explanation. But basically a CPU is an electronic device that runs on electrical current, and just like an electric motor as you raise the RPMs/Mhz it draws more current.
Manufacturers include voltage headroom in the stock specification to ensure stability and provide for variations in chip quality(Thats why you can overclock to a point on stock voltage). Every chip performs differently, some will overclock quite high just with stock voltage, some will acheive a high overclock but will require more voltage, and some don't overclock very well regardless of voltage
And yes voltage does create heat. Thats why hardcore overclockers use alternative cooling methods like water cooling, Vapochill, etc... Personally I use high end air cooling, many people are getting great overclocks wth stock cooling but in my opinion temps get to high with stock cooling. A64 chips will run stable with load temps up to 68-69c, but at these temps your most likely shortening the lifespan of your chip considerably. With good air cooling you can achieve a max overclock and keep your load temps less than 55c wich should give a much better lifespan of the chip
Manufacturers include voltage headroom in the stock specification to ensure stability and provide for variations in chip quality(Thats why you can overclock to a point on stock voltage). Every chip performs differently, some will overclock quite high just with stock voltage, some will acheive a high overclock but will require more voltage, and some don't overclock very well regardless of voltage
And yes voltage does create heat. Thats why hardcore overclockers use alternative cooling methods like water cooling, Vapochill, etc... Personally I use high end air cooling, many people are getting great overclocks wth stock cooling but in my opinion temps get to high with stock cooling. A64 chips will run stable with load temps up to 68-69c, but at these temps your most likely shortening the lifespan of your chip considerably. With good air cooling you can achieve a max overclock and keep your load temps less than 55c wich should give a much better lifespan of the chip
Machine350
Senior member
Yeah from what I've heard, overclocking cuts the life down from like 10 years to like 3-5, depending on how far you overclock. That really isn't much of a problem considering in 2 years, your crap is pretty much outdated.
imported_whatever
Platinum Member
considering that stock voltage for the normal a64 is 1.55v, 1.425v is still not going to shorten the lifespan (well maybe from like 50 years to 30 or something, but you get the point)
GuitarDaddy
Lifer
Each chip is different and any numbers are theoretical, so trying to determine the lifespan of a chip at stock speeds is impossible, and even more so for an overclocked chip.
But one things is for sure.
Heat (not speed) reduces the life of the chip, therefore the higher you run your temps the shorter the lifespan, and if your temps regularly peak at near the max temps the CPU can handle 68-69c the damaging affect will be multiplied.
But one things is for sure.
Heat (not speed) reduces the life of the chip, therefore the higher you run your temps the shorter the lifespan, and if your temps regularly peak at near the max temps the CPU can handle 68-69c the damaging affect will be multiplied.
GuitarDaddy
Lifer
MisterChief
Banned
:shocked:
Jeff7181
Lifer
Here's the way I understand it...
Transistor are switches operated by electrical current. Below a certain voltage, the switch is open... above a certain voltage, the switch is closed. When you increase the speed at which the transistor has to switch from open to closed, which is now billions of times per second with multi-GHz processors, the time it takes for the voltage to rise to the point at which the switch is "closed" is too short and a 0 stays a 0 rather than becoming a 1. If you increase the voltage, which is electrical pressure, it reduces the time it takes for the voltage to rise because there's more eletrical force which causes current flow. But... increasing electrical pressure increases the amount of current leakage, which is basically a small amount of current flowing through a transistor that is supposed to be open. (imagine a small leak in a garden hose, and how more water leaks out if the water pressure is increased) More current leakage = more heat... and heat increases the resistance of a conductor (or semi-conductor in the case of a CPU)... so now it's even more difficult for the voltage to rise to the point at which the transistor is closed. This is why an overclock may be perfectly stable at 40 degrees C, but may become unstable at 60 degrees C.
Transistor are switches operated by electrical current. Below a certain voltage, the switch is open... above a certain voltage, the switch is closed. When you increase the speed at which the transistor has to switch from open to closed, which is now billions of times per second with multi-GHz processors, the time it takes for the voltage to rise to the point at which the switch is "closed" is too short and a 0 stays a 0 rather than becoming a 1. If you increase the voltage, which is electrical pressure, it reduces the time it takes for the voltage to rise because there's more eletrical force which causes current flow. But... increasing electrical pressure increases the amount of current leakage, which is basically a small amount of current flowing through a transistor that is supposed to be open. (imagine a small leak in a garden hose, and how more water leaks out if the water pressure is increased) More current leakage = more heat... and heat increases the resistance of a conductor (or semi-conductor in the case of a CPU)... so now it's even more difficult for the voltage to rise to the point at which the transistor is closed. This is why an overclock may be perfectly stable at 40 degrees C, but may become unstable at 60 degrees C.
I'm not sure if you are getting the answer you are looking for.
Here is my understanding of it:
Chips are engineered to certain operating points. Hopefully, when they are fabricated it alll turns out dead correct, but probably not. Every chip comes out different, although the ones in the same run turn out mostly very close. The supply voltage is one operating point. The switching point of the transistors, low to high and back, is another operating point. Altering the supply voltage also moves the switching points of the transistors slightly, the voltage/current at which the transistor changes from a low state to a high state, and visa versa. The net effect, though, is that the rate of change of the voltage/current is a little steeper at a higher voltage. That is critical when the CPU is operating near its upper speed limit. So it reaches the point of switching faster. Raising the voltage would always increase the switching speed, except that, as you noted, it also has other effects that go against that.
Cool transistors switch faster than warm transistors. It has something to do with thermal electrons, that is electrons moving radomly due to heat, interfering with signal electrons. That makes it harder to switch from one state to another. At absolute zero, transistors hit their maximum speed. I think it is something like 30% faster than room temp. The applied voltage also determines the average energy and therefore also the heat generated and temperature. You could possibly hit the point where changing the voltage does more harm than good. However I think most OC limits are reached before that and are due to irregularities between transistors causing a lack of synchonization between things that need to be eactly at the right time. It's just that the switching speed is one part of the problem.
It is incorrect to think that voltage is not a killer. The insulators in the field effect transistors, and elsewhere, are very thin. The breakdown voltage, that is the voltage at which the insulating properties break down and there is conduction through the insulator, most probably catastrophic, is not much higher than the normal operating voltage. It normally does not need to be much higher, and there are reasons that a thin insulator is a good thing. One transistor in 100 milliion not working right likely would make the CPU non-functional. This mechanism is probably the chief cause of sudden failure. However, as long as the voltage is below the breakdown, it wouldn't decrease the chip lifetime.
It is probably true that the failure of an insulator is at slightly higher voltage when it is cooler. Just a guess. But if so, I doubt that 20 degrees would be significant. Without hearing it from a professinal in the fab bussiness, I would not believe that cooling noticeably protects transistors from the breakdown effect.
I am told that there is such a thing as chip lifetime. I guess something gradually happens to the doping structure that makes transistors what they are, and that is accelerated by increased temperature. I never ran into anyone who claimed that his chip had died due to this though. (Although, how would they know?) What I have read is that chips that are examined for failures (when they are operated under proper conditions) almost always fail due to an undiscovered defect present in the manufacture. Maybe a failure in the weld that connects the pins to the chip, or a too-thin spot in an interconnect. Something like that. So they "burn in" chips at the factory to try to get them to fail there. They subject chips to things they should not encounter normally. One person who does this at the factory said that the chips invariably come through working at a slower speed than before. DANG. I wish they'd let us have some without the torture test.
The only old chip (5 years?) that I ever tried out again actually OCed a little higher than it did before, probably because chipsets have improved since. This chip had been OCed to its stable max its entire lifetime (about 2 1/2 years) before it was retired.
Here is my understanding of it:
Chips are engineered to certain operating points. Hopefully, when they are fabricated it alll turns out dead correct, but probably not. Every chip comes out different, although the ones in the same run turn out mostly very close. The supply voltage is one operating point. The switching point of the transistors, low to high and back, is another operating point. Altering the supply voltage also moves the switching points of the transistors slightly, the voltage/current at which the transistor changes from a low state to a high state, and visa versa. The net effect, though, is that the rate of change of the voltage/current is a little steeper at a higher voltage. That is critical when the CPU is operating near its upper speed limit. So it reaches the point of switching faster. Raising the voltage would always increase the switching speed, except that, as you noted, it also has other effects that go against that.
Cool transistors switch faster than warm transistors. It has something to do with thermal electrons, that is electrons moving radomly due to heat, interfering with signal electrons. That makes it harder to switch from one state to another. At absolute zero, transistors hit their maximum speed. I think it is something like 30% faster than room temp. The applied voltage also determines the average energy and therefore also the heat generated and temperature. You could possibly hit the point where changing the voltage does more harm than good. However I think most OC limits are reached before that and are due to irregularities between transistors causing a lack of synchonization between things that need to be eactly at the right time. It's just that the switching speed is one part of the problem.
It is incorrect to think that voltage is not a killer. The insulators in the field effect transistors, and elsewhere, are very thin. The breakdown voltage, that is the voltage at which the insulating properties break down and there is conduction through the insulator, most probably catastrophic, is not much higher than the normal operating voltage. It normally does not need to be much higher, and there are reasons that a thin insulator is a good thing. One transistor in 100 milliion not working right likely would make the CPU non-functional. This mechanism is probably the chief cause of sudden failure. However, as long as the voltage is below the breakdown, it wouldn't decrease the chip lifetime.
It is probably true that the failure of an insulator is at slightly higher voltage when it is cooler. Just a guess. But if so, I doubt that 20 degrees would be significant. Without hearing it from a professinal in the fab bussiness, I would not believe that cooling noticeably protects transistors from the breakdown effect.
I am told that there is such a thing as chip lifetime. I guess something gradually happens to the doping structure that makes transistors what they are, and that is accelerated by increased temperature. I never ran into anyone who claimed that his chip had died due to this though. (Although, how would they know?) What I have read is that chips that are examined for failures (when they are operated under proper conditions) almost always fail due to an undiscovered defect present in the manufacture. Maybe a failure in the weld that connects the pins to the chip, or a too-thin spot in an interconnect. Something like that. So they "burn in" chips at the factory to try to get them to fail there. They subject chips to things they should not encounter normally. One person who does this at the factory said that the chips invariably come through working at a slower speed than before. DANG. I wish they'd let us have some without the torture test.
The only old chip (5 years?) that I ever tried out again actually OCed a little higher than it did before, probably because chipsets have improved since. This chip had been OCed to its stable max its entire lifetime (about 2 1/2 years) before it was retired.