E8400: voltage, VID, temps, electromigration and lifespan - Page 3

Understand and Avoid Electromigration (EM) & IR-drop in Custom IP Blocks

I get brain lock just reading it. Too many terms outside my experience. Maybe Duckie Ho would know?

Single stage phase, at -42°C, and just for hwbot, so not stable....well, CPUZ stable

The 2500K though, just on a Corsair H50....

Electromigration happens all the time at any voltage & temperature. It greatly increases as you increases the voltage & the temperature. Why? Material resistance is proportional to temperature. If you also increases the amount of electron (delta potential = voltage), more electrons will collide.

Extreme OCers do not use liquid gaz mainly because it is very cold. The main advantage is that you get very low resistance reducing electron collision hence allowing a greater current flow (more voltage).

Increasing temperature => increases resistance => increases collisions => increases electromigration

Increasing voltage => increases odds of a collision since there are more electron "flowing" => more electromigration

The thing that is damaging the most CPU and electronics components are cosmic rays. These are bombarding the earths of very fast particles interacting especially with electronic components. Your CPU risk to die more due to that than electromigration. Intel has built their chip to deal with that phenomenon. You might lose performance in the long term but that is a very slow process.

http://en.wikipedia.org/wiki/Electromigration

Heat caused by collisions that are causing electromigration. Heat increases the molecular vibration thus increasing the odds of collisions.

With no molecular vibration (very low temperature), the lattice structure is nearly perfect hence less resistance causing less collisions.

60C to 80C will make a difference but will it be noticeable? I doubt.

I can do 5GHz with this CPU quite easily but 5.2GHz requires a lot of extra voltage.

I run it at 4.2GHz every day use because I never came across a game that would requires extra CPU juices. Stock speed would even be fine as lately I rarely game and the GPU is the actual limiting factor. It is useless to waste energy/efficiency running it at 5GHz for me.
In your situation, ask yourself if you do need those maybe 100-200 extra MHz at the cost of extra heat/voltage & risk your chip degrades much faster. There is no graph but considering efficiency is not linear with heat/voltage used, I tend to think degradation is exponential with heat/voltage used too. Transistors are conceived to work with a range of voltage (VID). More or less voltage and the efficiency greatly reduces (even with low voltage efficiency can also not be optimal).

I would prefer put the money into a new GPU instead of replacing my CPU/mobo. You can sell your graphic card (100$) to get a 7870 (200$) by example. A 4GHz E8400 will barely bottleneck the GPU (as far as I know)...

Edit :

Oh and you know you can sell your CPU/mobo instead of killing the CPU? I am sure some one might be interested since your CPU seems to be a good clocker (frequency is scaling with voltage ; no wall). Under extreme cooling it may be able to get something interesting? Who knows?

I sold my i5-750 with his motherboard for 200$. You might get less for your combo but some one could still be interested. Instead of killing the CPU to get a new system, why not sell it to help you upgrading?

I personally upgraded at a null cost by selling my i7-870 & my EVGA classified 200 to a 2600k & z77x-ud3h and seriously that was such an awesome upgrade. System running cooler, overclock like a charm, etc. I am very happy with it
Edited by Just a nickname - 12/22/12 at 12:56pm