Intel – Selecting Components for a CAD Desktop

Take advantage of development cycles to get best price and performance.

This post will set out the first step in how I would start selecting Intel components for a reasonably priced CAD desktop computer.  The assumptions are that I’m running a mid-range CAD software designing mostly prismatic parts and with some moderate surfacing.  Only a few components contain complex geometry and the assemblies contain a few hundred unique components with only a couple thousand total components.  I perform only occasional finite element analysis and rendering, so although I need to crunch numbers I can usually schedule that effort for overnight or over-weekend runs.

Intel has long been using what it refers to as the tick-tock cycle of CPU model generation and development.  The TICK cycle is a shrinking of the process technology.  Shrinking the technology includes changing the manufacturing process of an existing chip design in order to fit more transistors onto the same piece of silicone.  For example, the TICK cycle is when processors shrink from 32nm to 22nm.  The TOCK cycle is a new microarchitecture.  This is a completely new layout to the transistors, but uses the same manufacturing process.  CAD users interested in purchasing a new workstation can use this information to find the best price and best stability in hardware.

The Right Chip for CAD, CAE, and CAM

Intel alone has far too many choices when selecting a processor.  To narrow down the comparison for this post, I’m limiting the selection to what Intel refers to as its High End Desktop Processors.  The reason for this limitation is because there are certain features a typical CAD, CAE, CAM, or rendering user should focus on in a CPU.  Intel’s self-designated High End Desktop Processors fit those criteria nicely.

Although geometry kernels like Parasolid and ACIS are slowly taking advantage of multi-threading, the bigger benefit is a faster processor speed compared to more cores.  The cache size determines how much data can be stored within the CPU itself for processing before having to use the slow bus to get to data stored in RAM or on disc.  Inevitably, though, data is going to have to be moved around the computer, so more and faster memory will start to be noticed, but usually not unless you have very large assemblies or very complex geometry.  And of course, if the data can’t be displayed on the monitor fast enough, no amount of processer speed will help the user.  Therefore the pipeline to get the data displayed to the monitor is the final leg in the race.  Since discrete graphics cards are using the PCI Express standard, the latest and greatest version supported by the CPU means that users can realize the benefits from the latest and greatest graphics cards.  Finally, keeping things cool and energy efficient is just smart business.

High End Desktop Processors

The key word here is “desktop.”  Although we’d all like to work on high end workstations, the fact of the matter is that most of us are stuck with some form of desktop computers.  Desktop computers differ from workstations on a few key features such as ECC memory and dual chips.  In this case, because high end users typically require discrete graphics cards, Intel classifies these CPUs for high end desktops that don’t contain internal graphics processors. 

The Core i7 Standard

Conspicuously missing from the table are anything but Core i7 processors.  This is because Core i7 are the processors with four or more cores.  The Core i3 only have two cores and the Core i5 typically have two cores, but some may come with four depending on the generation.  The XEON processors are in a class all by themselves.  With clock speeds for each Core model hovering in the same GHz, selecting the model with more cores will yield better benefits.  Of course, Core i3 and Core i5 do run on lower power and therefore a bit cooler as well.  If a quiet computer is your thing, then don’t overlook a Core i5.

Each processor is 64-bits and supports up to 64Gb of memory.  The Ivy Bridge processors support faster memory than the older generation Sandy Bridge.  But none of them support ECC memory, which is a heavier weighted criterion if your focus is more toward simulation than it is CAD, CAM, or rendering.  If you find that most of your workload is FEA and simulation, then this post may not be for you.

To support the latest in discrete graphics cards that use the PCI Express 3.0 standard, our choices are automatically made for us.  Our choices are quickly narrowed to Ivy Bridge processors.  From there, there are only a few differences between each of the models: clock speed, cache size, and cost.  Considering that the fastest clock speed is also the lowest price, I now have my CPU selected and can start designing the rest of the system around it.

What Intel Chip Would I Choose for a CAD Desktop?

Starting with recommendations based on Intel’s website, I quickly narrowed my choice of CPU to seven possibilities.  Three are the current generation processor and four are older generation processors.  Because I want to design longevity into my system, I chose the current generation processor that supports the latest in computer standards, like PCI Express 3.0.  From that point, it was easy to find the least expensive CPU ($325 vs up to $1,050) that also conveniently had the fastest clock speed making my choice of an Intel Core i7-4820K processor a no brainer.  (Prices current at the time this article was written. Your mileage may vary.)