It's not about needing a world-class heatsink/cooler... more about preserving the life expectancy of your CPU. The cooler you keep it the longer it is likely to last... and most stock coolers are largely inadequate, partiularly for overclockers.
Not exactly. It's also about reliability in the now as well. As it runs hotter, the atoms are randomly bouncing around faster and faster. And when you're at 45nm technology and running at 1.2V (which is ungodly low), that matters. You'll start getting random 1's instead of 0's. And as you know with computers, that only has to happen once and your whole session crashes. But still, the Phenom II's run at 125W while the I7 920's are at 130W, so it's a wash. Yeah, the stock coolers weren't designed with overclocking in mind. Last I remember, Intel was engineering their processors to last 7 years. But with the heated competition (pun intended), it wouldn't surprise me if they lowered that to 5. You of course lower that further with overclocking, but the idea is, who cares...it was 7 years to begin with. I only need 3.
This argument has a false premise. Fabrication techniques improve over time for any given factory, so a core i7 920 found in stores today is likely to be far more stable (and overclockable) than a core i7 that you bought a year ago. Oftentimes the only difference between specific processors from a given line is how they "test." I'm not sure if this is the case between the 860 and 920, but it's likely that they come from the same factory and production line, they simply label and assign different clock/multipliers to them depending on how they test.
Yeah, the basic idea is, if the processor passes at 3.33 GHz it's labelled a 965. If it fails but passes 3.0 GHz, it's a 950. If it fails but passes 2.6 GHz, it's a 920. So for overclocking, you want the top-of-the-line. Unfortunately with i7's that runs a cool $999. You can still overclock the lower-ends, but what you're doing is cutting into the margin Intel built in to account for reliability, like I mentioned earlier.
Fabrication techniques do improve over time, but when you're talking the same processor, on the same process, you're talking incremental improvements intended to improve yield. What they do is enrich silicon (just like enriched uranium), and then they try to get the maximum number of working parts off of one wafer that they can. More working parts = more money for them. And of course they make more money if they get more passing 965's than they do 920's, so they are trying to make it incrementally faster. I don't know that that means a given 920 off the shelf will be more stable, though. Just means they will slash the prices on the 965 one day, when they get suitable yield on it. Which is what you want, because that is what you want to overclock.
