Navigate the Evolving Choices for CAD Workstation CPUs, Part 2

14 Mar, 2018 By: Alex Herrera

Herrera on Hardware: In a changing CPU market, which brands and models should you should consider for your next CAD workstation?


Which Brands and Models Should You Consider for Your Next CAD Workstation?

In contrast to the past decade, which presented a fairly straightforward choice in CPU brands — Xeon or Core i7 — market dynamics are creating more choices in 2018. Core i9 is now in the mix, dramatically closing the differentiation gap with Xeon, and AMD is knocking on the door with not one or two but a complete family of CPUs that can contend for consideration. Next up, I’ll try to boil all those factors down into a step-by-step process to help guide the selection of your next CAD workstation CPU.

  1. Are you a single-socket (1S) or dual-socket (2S) user?

    This might sound like a tough question at first, but it’s probably not. The answer for the vast majority is “single socket,” as 85% of deskside workstations sold fit this category. The exception is that 15% minority which demands no-compromise performance for the most heavily threaded, compute-intensive applications. The bottom line is, dual-socket customers most likely know who they are, so if you can’t say you are one with confidence, stick with single-socket.
  2. Is reliability a crucial requirement?

    This might sound like a trick question; after all, every workstation buyer cares about reliability. But beyond the obvious preference, the salient question here is whether you or your application can tolerate even one outage or processing error in a year or lifetime. If not, or if you want to invest a bit more in ensuring the chances are kept to an absolute minimum, lean toward Xeon over Core. (For more details about that trade-off, check out my column on “The Hidden Danger of Memory Errors in CAD Computing.”)
  3. What’s your budget?

    Obviously, we all want the fastest machine available, but as always, performance and capabilities trade off with price. The average workstation sells for around $1,900, and the vast majority of workstations sold have price tags under $2,500. If your budget can tolerate something closer to $3,000, choose from premium-level 1S machines that offer primarily Xeon W, but as mentioned, may now be available with a Core i9 configuration as well. And though not (yet?) adopted by top-tier vendors HP, Dell, and Lenovo, AMD’s Threadripper makes for a possible option as well. If your budget needs to come in closer to or below $2,000, however, choose from an entry-level 1S machine that will offer primarily Intel Xeon E3 and Core i7 options (note that at least for now, the Ryzen 7 or Ryzen Pro options are slim to none). And finally, if budgets are really tight, then you can consider side-stepping all these options and select the far more economical Core i5.

At this point, you’ll hopefully narrowed down your choices to one brand or product line: It will most likely be Core i7, Core i9, Xeon E3, or Xeon W, but perhaps even one of the emerging AMD options. The last choice to make is among the specific model stock-keeping units (SKUs), which tend to vary by core count and clock frequency. As discussed, OEMs will present you a variety of options populating anywhere from four to 18 cores, and the more cores you choose, the lower the clock frequency of those cores. That means — in general — that the more you optimize your CPU SKU choice to maximize cores, the slower your single-thread performance will be. And vice versa, the more you maximize frequency, the more your multi-thread performance will likely suffer. (And for a great example of that inverse relationship, check out this column, where I compare performance of a modestly clocked, 16-core Threadripper and an extreme-clocked 4-core Core i7.)

Given that trade-off, if you spend your day running single-threaded tasks (e.g., modeling, interactive 3D graphics) nonstop, then you’ll probably want to focus on Core i7 and Xeon E3 or W SKUs with higher clock rates and lower core counts (four to eight cores). But if you are just as likely to have your day throttled by big, heavily threaded rendering or simulation jobs, you’ll want to consider moving to a Xeon W, Core i9, or Threadripper with ten or more cores.

One last caveat to keep in mind: Consider that around 75% of workstation CPUs sold today populate four cores or fewer. So while the CPU options that triple or even quadruple core counts are featured prominently in workstation marketing collateral, today’s reality is that the vast majority of CAD users are running — and all evidence would say, effectively running — with quad-core CPUs.

Why are shipments so lopsided in favor of low-core-count CPUs? The answer is three-fold. First and most notably, the users more concerned with single-thread performance appear to dramatically outnumber those more sensitive to multi-thread performance. Second, applications that implement multi-threading effectively continue to lag behind CPUs that afford more multi-threading. And third, although Intel and OEMs are certainly making higher core count options available, they haven’t gone overboard pushing those options into the market, because of the first two reasons listed.

When it comes to the options available in workstation-caliber CPUs for CAD professionals, 2018 is shaping up to be the most interesting year in more than a decade. OEMs and users alike are seeing an expanding choice of brands and configurations to choose from. And while that might make for a more challenging shopping exercise, a few simple guidelines can help you narrow choices down quickly and outfit your next CAD machine with an optimal CPU for your workload — at an ever-more-aggressive price point.

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About the Author: Alex Herrera

Alex Herrera

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