AMD Phenom II 955 BE Overclocked to 7.0GHz

[Jason Dunn]

<div class='os_post_top_link'><a href='http://news.softpedia.com/news/AMD-Phenom-II-955-BE-Hits-7-0GHz-115985.shtml' target='_blank'>http://news.softpedia.com/news/AMD-...Hz-115985.shtml</a><br /><br /></div><p><em>"Sunnyvale-based Advanced Micro Devices wants to show the world that its processors are capable of breaking the world records when it comes to their overclocking capabilities. As such, the company sponsored an overclocking event in Finland, where its AMD Phenom II 955 Black Edition processor was pushed up to the impressive speed of 7.0GHz, a figure that might become a new world record in case the results are validated."</em></p><p>7 Ghz? Sweet mother of motherboards! That's...insane. I drool at the thought of encoding h.264 video at 7 Ghz. So the question is, if this new chip is capable of insane speeds like that, why don't we see chips in the more "mundane" range of 4 Ghz or 5 Ghz? Power consumption? Stability? Longevity of chips? I'd happily accept a 5 Ghz chip that only lasted 36 months if I knew it would be stable during that period.</p>

[Janak Parekh]

Probably diminishing returns. Keep in mind that clock rate isn't linearly equivalent to processing speed. It takes some time for processors to do work in each stage; the traditional way of pumping up the clock would be to increase the number of stages and decrease the amount of work done in each stage, but such a deeper pipeline causes performance issues when processing needs to "flush" the pipeline (the Pentium 4 is the classic example of this). The more common strategy nowadays is to increase the amount of work done in each stage and not bother so much with the clock rate.

Now, to the question of why one couldn't take a 3GHz relatively-shallow-pipeline processor and overclock it: I guess they could. But, we don't know all the parameters of this solution. Maybe it will work for an hour before it misbehaves. Or, maybe there will be silent bit errors being introduced. Or, perhaps the yield of CPUs that can go this far is very low.

--janak