Helping people with computers... one answer at a time.
I've read that AMD's 2.0 GHz processors are comparable to Intel's 3.0 GHz processors. That seems totally counter intuitive. Why would that be?
To be totally honest, this is one of those areas that I actually spend very little time on. There are hardware geeks out there that will happy rant and rave at how one is better than the other. In fact, I kinda hope some of them will enlighten us with a comment on this article.
But clearly, all Gigahertz are not created equal.
In general, as your question alludes to, there's much more than gigahertz playing a factor in how fast your computer operates. It is a combination of the processor's internal architecture, the efficiency of its interfaces to the motherboard, the composition of the motherboard itself and other items that all combine to make systems faster, or slower, when compared to others. On top of that, add the efficiency of many peripheral devices like your video adapter which can also have a dramatic effect on the speed, or the perceived speed, of your computer.
I couldn't tell you the equation, but I know it's complex. :-)
What I can tell you is that I don't think it's worth spending a lot of energy on, unless it's a matter of curiosity or you really have a need to squeeze every last bit of performance out of your machine.
Personally, I look at the applications and load that the server will be handling. If you expect to get "close" to stressing the slower of the two processors, in my mind, you're too close for the other one as well. A 20% difference, for example, in throughput between two processors is not make or break to me. What is is cost, and other factors that add up to, say, 100% or greater differences. So when selecting a server, which I have done in recent years, I try to look at the total picture ... cost, disk capacity & speed, network bandwidth, memory usage and capacity, my expectations for video performance ... and somewhere in the middle of all that ... processor speed.
But that's just me.