Which computer company builds the best workstation???
I used to work at HP on Intel based high performance network servers in the ME department. I used to talk with Intel every week to get its roadmap and technical details.
As for AMD, I don't know its processors as intimately as Intel's since I didn't work on it. However, it should be as good as Intel's. In general, AMD's processors don't have any large L2 cache processors such as Intel's Xeon processors, which are designed for high-performance servers. It is comparable to Intel's desktop processors, such as PIII and P4. As long as you are comparing to these processors AMD's should be comparable.
Best way to figure out which processor and what configuration is to look up the trade magazines for your specific application that have done performance bench mark for the different processors and configurations for the software that you are planning to run. In your case look in to the CAD magazines.
In general most of the Mechanical CAD packages that I am aware of are not multi-threaded, i.e. they can not take advantage of mutli-processing. Therefore, one doesn't really need a multi-processing machine for that instance.
For speed it is also recommended to run the working model locally in order to minimize the network traffic delay, or a very fast and small local network to hook up the CAD stations. However, most CAD data base has to be shared amongst different users and therefore it needs to reside on some sort of a network. But, if the working models are local, you would prefer high speed disk access, therefore, you will need higher speed hard drives and SCSI interface. Don't just settle for 7,500 RPM hard drives with EIDE controller.
Suggestions for a CAD station:
1. Fast graphics card with a lot of memory for 3-D rendering and dynamic viewing.
2. A lot of RAM, minimum 1Gig for most large system models.
3. Fast processor.
4. High bus speed.
5. 10k RPM HDD with SCSI interface.
For Items 3 and 4, one needs to look at bench mark results for the proper combination.
For professional applications, it is recommended to buy name-brand systems from such vendors as IBM, HP, or Compaq, because the systems are fully tested for reliability as well as software compatibility. The no-name clone brands generally are not tested and one will spend a lot of time patching the system up as you go. If you are a computer enthusiast and have all the time to mug around with the hardware and software than by all means to go with a clone machine.