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JB Escreveu:acho que é desta q eu me vou aventurar no OC (se bem q ja fiz num PIII mas nada de especial 550@616 mhz).
Pois.. pk o a minha config (ver assinatura) merece um OC... pois pk ter esta machine e nao fazer OC... é como ir ao Mc e nao comer um Super Sunday..
...mas antes de ir ao Mc tenho de comprar um cooler de gente (talvez o Thermalright XP-90 C).
Como é a massa térmica? tb tenho de comprar uma boa não é? se sim qual?
Já agora por acaso nao dá pa mudar o cooler do chipset da board?... é q o de origem faz um cado de barulho... o problema é q tem a gráfica em cima...
se alguem quizer dar uma ajudinha extra para o OC... agradecia.. mas acho que já me desenrasco.. p ois à aki ppl q tem uma config parecida com a minha com OC bem cool (em stock coolling).
cya







pm (mais técnico) Escreveu:I have mostly been taking a break from the CPU forum - and actually AT in general - due to too much general flaming going on and the fact that I'm in between hardware upgrade cycles (and thus aren't paying a lot of attention to hardware). I still read on here periodically to see the scuttlebutt on forthcoming processors. So, my lack of posting has more to do with a general lack of reading on Anandtech. I plan on upgrading sometime this summer so as we get closer, I'll likely start posting a fair bit more.
The third Intel poster you are probably thinking of Rich is "dmens".
As far as the original question:
There's a linear dependence on mean-time to fail (MTTF) on a CMOS part to temperature, there's a square dependence on voltage to MTTF.
In non-statistics speak, increasing the temperature a bit will make your chip a little more likely to die. Increasing the voltage a little bit will have a much bigger statistical liklihood to kill your chip.
In the "old days" - prior to 0.18um process technology - the dominant reliability failure mechanism was electromigration... although this depended a fair bit on the design and the design rules used by the manufacturer. In electromigration, higher temperatures and higher voltages reduce the average time to failure. Because electromigration is dependent on current density, increasing voltage is worse.
Once the industry switched to dual-damascene copper technology, electromigration failures were relegated back to design-related mistakes. Instead the dominant failure mechanisms became time-depenedent dielectric breakdown (TDDB), PMOS BTI (although this is pretty much accounted for in manufacturer burn-in), and NMOS hot-electron gate-impact ionization (NMOS hot-e). In all three of these small increases in voltage can result in large reductions in operational lifetime, and small increases in temperature, result in generally small reductions in operational lifetime - in fact, in the case of NMOS hot-e, it gets worse with lowered temperature.
All three of these are quantum mechanical effects. If anyone is really curious, I can go into more details to explain exactly what is happening. For more details, you can read through this (rather condensed, somewhat esoteric but fundamentally correct) notes page http://www.eie.polyu.edu.hk/~ensurya/lect_notes/Reli_Fail/Reli_Fail_notes.htm. Although the whole page is an interesting reference, the part relevant to this discussion starts with "Properties of Metal-Oxide Silicon (MOS) System". Or Google, "NMOS hot-electron", "PMOS Bias Temperature Instability" and/or "time-depenedent dielectric breakdown", I can also give more detailed IEEE journal publications too if anyone wants them.
Patrick Mahoney
Enterprise Processor Division
Intel Corp.
pm (inglês "comum") Escreveu:Sorry, it's hard to gauge how technically I should answer a question. If I don't make it technical then I feel like I'm not really being very accurate... I think it's an engineering trait, I notice my co-workers do this a lot too.
Sorry, I can't do l33t speak. So I'll have to try English.
There are 4 ways that chips break:
electromigration: metal atoms in a wire move around because lots of lots of electrons hit them. Move enough metal atoms and the wire will either short with another wire, or have a hole in it and stop working.
TDDB: the insulation material that separates two key parts of a transistor breaks down creating an electrical short - which breaks the transistor. In most cases, if any one of the hundreds of millions of transistors breaks, it will break the chip.
hot-e: a key parameter of the transistor called "Vt" (threshold voltage) shifts over time - which essentially slows the transistor down. If it slows down enough, then the chip will calculate an incorrect value.
BTI: Similar to hot-e but for a different type of transistors and happens for a different reason. Usually fixed in the factory.
In all but hot-e, increasing the temperature a little makes the chip a little more likely to break (this is all statistics... there is no "do this and this will kill your chip..." it's all a matter of probability). In hot-e, lowering the temperature makes it worse.
In all of these, increasing the voltage a small amount makes them much more likely to break the chip.
As to why 10% more voltage is much worse than 10% more temperature, well let's take the example of electromigration and look at it in detail.
Wires are made up of atoms all lined up. Electrons flow through these atoms. An electron is a very small thing, and atoms are a lot bigger. So the idea of an electron moving an atom around is a lot like someone trying to move a car (atom) by shooting a BB (electron) at it. Clearly to ever hope to move a car by shooting BB's at it, you would need a lot of BB's... a storm of BB's. But if you get enough, the car will move. Millions of BB's and that car will likely start getting pushed around. The temperature of the chip could be thought of as how slippery the road is. A little bit more slipperiness isn't going to help a BB move a car. It helps a little but not a lot. On the other hand, the voltage determines how many BB's you have, and it's not like 10% more voltage is 10% more BB's (electrons), you get a lot more than 10%. And worse than that, because increasing the voltage in a chip also increases the temperature (all things being equal, like same heatsink, same air temp, etc.), increasing the voltage is a double-whammy.
The others are similar... but more complex to explain (I'm still not sure that the experts really completely understand the low-level details of both TDDB and BTI...).


CAS# 2
RAS# 3
RAS# to CAS# 3
Precharge Delay# 6
DDR – 360 vDIMM – 2,6V
as memorias demoram X tempo a efectuar acçoes diferentes. esses valores (timings ou latencias) identifikam o tempo k a memoria demora a fazer essa determinada acçao. quanto mais baixos melhores e alguns valores teem mais importancia do que outros como eh por exemplo o CAS



tintoll Escreveu:boas!!!
desculpem voltar a tocar no assumto mas tou mesmo enrascado.
queria aumentar o overclock ao meu processador mas tou com um bocado de dúvidas porque não sei qual cooler eide comprar.
alguem me diz um cooler para aumentar um p4 2.4 pa um 3.0 ou 3.2 ou 3.4?
ajudem-me pff é urgemte obrigado...

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