Efficiency And Value Analysis
First, let’s take a look at the most underwhelming chart of this little experiment:
When it comes to gaming, even a 2.4 GHz Xeon E5620 delivers 96% of the performance made available by a Core i7-930 overclocked to 4 GHz. That’s pretty darn damning.
As you shift over to A/V- and productivity-oriented apps, the overclocked Xeon manages to establish a slim victory at the same frequency as Intel’s Core i7-930. But it’s the Core i7-970 that pulls the largest lead, thanks to its six cores.
Factor power consumption into the picture and the focus gets a little sharper. The stock Xeon E5620 is about 75% as fast as the Core i7-930 overclocked to 4 GHz, but it also uses 75% of the power. And as a result, it’s as efficient. Overclocked, the same CPU sports 102% of the i7’s performance, yet it only uses 92% of its power, thanks to 32 nm manufacturing. Thus, it gains a more significant efficiency advantage. Finally, the Gulftown-based Core i7-970 is much faster in our thread-optimized benchmark suite, it uses less power than the quad-core i7-930, and so it’s the most efficient CPU being tested.
This chart knocks Intel’s second-best desktop chip off of its high horse in a big way, though. A price tag more than 300% higher than the Core i7-930 means you only get 38% of the Bloomfield chip’s value, as measured by average performance over price.
Because it’s sold at such an attractive price, the Core i7-930 at 4 GHz actually gives you the best value of the group. Remember, though, that it takes a bit of coaxing to get this retail chip stable at 4 GHz—including one of the highest-end air coolers available. Remember also that the Xeon E5620 can actually be coaxed up to 4.2 GHz or so if you’re willing to pull out the stops and break the 220 MHz BCLK ceiling. So, this chart doesn't tell the whole tale. A Xeon E5620 will likely buy you more performance than the Core i7-930, which we'd scale back to 3.73 GHz anyway.