Intel x86 CPUs
Interview with Christian Bayer
Christian passed away in 2006
March 11, 2005
Editor's Note:Trying to keep up with Intel processors can be difficult. If you don't keep up, it's very confusing when you have to make a computer purchase decision. In a recent e-mail interview with Christian Bayer, he shed some light on some of the following questions. If you have additional questions about CPUs, send them to info@panug.org or info.biznix.org and Christian may answer them when he has time.
What's the difference between a desktop chip and a server chip?
Sometimes the difference between server, desktop (and laptop) CPUs is just stuff like heat generation and power consumption, other times it is only a matter of marketing. The 1.3 GHz and 1.4 GHz Pentium IIIs were server CPUs. They were not really available to anyone except OEMs although they significanly outperform P4s at the same clock speed. They wanted desktop machines to use the new Pentium 4 but it was too hot to put into a blade or low-profile rack server. My laptop has a desktop 2.8 GHz P4 in it but I sure wish it was a Pentium M because it really gets hot and the fan required to keep it from overheating is quite noisy.
What is a Pentium M?
Many people believe the Pentium M is an evolution of the Pentium III. A Pentium M is faster (as in get more done in the same amount of time) than a Pentium 4 at the same clock speed.
Why is a 2 GHz Pentium M about as fast as a 3 GHz Pentium 4?
The Pentium 4 was designed to scale to 10 GHz so the architecture was built with many more pipelines than the Pentium III and Pentium M so it could scale to greater levels. If/when the P4 gets closer to 10 GHz the benefit of the design will be realized but on the low end they only slow the chip down.
What's an Itanium?
An overhyped, underselling Intel 64-bit processor that was supposed to fill the former role of the Digital Alpha and HP PA-RISC CPUs. Nobody seems to have much interest in it, not even HP who is nearly as responsible for its existence as Intel. Basically, if you don't know, it probably doesn't matter. The new AMD 64-bit chips seem to be much more interesting to manufacturers - Sun for example. The only other chip that appears to be a contender in this class is the IBM Power 4.
Why is the Itanium about sunk?
The Itanium's biggest cheerleader was HP. HP has lost focus and is losing traction. Instead of it's previous business model that was closer to IBM, HP has tried to shift towards one more like Dell. HP continues to divest itself of depth. They can't out-Dell Dell and they have lost a lot of ground by cutting R&D while trying to maximize short term returns. I predict that Carly's impact on HP has only begun to show in the decline of HP. As far as chips go, IBM has their Power series, so they are not interested in Itanium, developers aren't interested in Itanium, and customers aren't interested in Itanium. So, as HP is failing the Itanium goes with it. AMD 64 is much more attractive, even the likes of Sun are amongst it's purveyors.
The term "x86_64" is used in Linux to describe the AMD 64-bit processors such as the Opteron and Athalon64. Is there an Intel processor that's in the x86_64 category?
Intel has implemented the AMD 64-bit instruction set in the Xeon.
What's the difference between the Opteron and Athalon64?
In a nutshell, the Athlon 64 can use 4 GB of memory and the Opteron can use 8 GB. The Opteron is intended for server use and some Opterons are designed for multiple processor configurations, although the Athlon 64 may be doing that too.
I want to build a Linux server that functions as a file server with 1 terabyte of disk space. It will also be running Apache Tomcat and numerous Java servlets. I'm thinking that an AMD Athalon64-based system makes sense. What do you think?
Probably an excellent choice, possibly massive overkill. You didn't mention how many users and whether you are running 64-bit Linux.