Specifying CAD Workstations, Demystified

12 Nov, 2013 By: Robert Green

Unsure about whether to direct your dollars toward a faster processor or more RAM? Here's one expert's opinion on what to choose for your CAD users.

In the previous edition of the CAD Manager's Newsletter, I made the argument that new workstations are actually a bargain, considering what they can do for your users. I also implored you to become more involved in specifying the workstations your company buys.

Now, I'll share some information that should take the guesswork out of specifying your CAD workstations and help you get the hardware you need to run CAD effectively. Here goes.

An Expert Perspective

I asked Intel Workstation Segment Manager Wes Shimanek to help CAD managers understand how to best configure workstations for their CAD users. Keeping in mind that there are many perspectives on this topic, I think you’ll find this information to be very helpful as you undertake future workstation upgrades.

One question I hear a lot has to do with the difference between Intel Core i5/i7 and Intel Xeon processors. Could you give us an idea of when each processor might be appropriate?
Great question; I get that one a lot too. Here is something I want your readers to consider: Professionals do not use personal computers to do design, they use workstations built for professionals. Workstations go through more testing and offer more features that can make a big difference in the speed and outcome of their project.

All of our processors are based on similar microarchitectures. What makes them different is what you surround them with. As an example, our entry-level Intel Xeon processor E3-1200v3 product family is surrounded with more advanced reliability and stability features. That means they are dependable; they will do what you ask them to do and they will probably have less demand for extended support services. Some of these processors also have access to our Intel HD Graphics P4600. Our HD graphics technology for professionals has come a long way in three years [and] now rivals many entry-level $150 discrete add-in cards for certain applications.

More advanced users doing photorealistic imaging and simulation or robust design activities will benefit from our Intel Xeon processor E5-2600v2 product family. These processors will present professionals with a more robust input/output [I/O] system, twice the memory bandwidth, larger caches, and a few more things, but I think you get the picture: These processors are built for demanding users who want to do a lot of work and iterate through more ideas than their peers who are using lesser devices.

One big difference in processors is cache. What should users look for in this regard?
Great point. Cache is generally thought of as king. The larger the cache, the greater the opportunity to reuse specific data and/or resources within relatively short time durations. If you can keep your data local and in the cache, you are more likely to experience a performance increase. Here is a quick way to look at cache: An Intel Xeon processor E3-1200v3 has 1.3 times more than an Intel Core i5, and an Intel Xeon processor E5-2600v2 can have up to five times more than an Intel Core i5 processor.

So many options exist for RAM size, speed, and error correcting code (ECC). What are the ground rules regarding what to purchase?
The first rule is, no matter what memory you use or which processor you buy, populate each memory channel equally. Whether you have two or four memory channels, populate all channels with memory modules of the same size and speed.

As for speed, invest in the fastest RAM your processor can support, because it makes a difference. As for how much RAM, the simple rule is that if you work with small 2D models, 8 GB is usually enough. For larger models, 16 GB makes a huge difference, and for very large models, 24 GB is even better. The goal is to eliminate swapping to the hard drive.

The performance monitor in Windows Task Manager can help you gauge whether workstation memory is sufficient. On this typical AutoCAD 2D user's desktop, an 8-GB RAM load is well suited to the user's standard workflow.

The ECC question is unfortunately the one most often overlooked by users. ECC memory protects your workstation from potential crashes and changes in data, as shown in the example below. More detail about the ramifications of memory error is available in this Intel technology brief.

According to a published Google study, one in three systems with just 4 GB of memory will have at least one correctable error each year, and more memory means the odds are even higher. A perspective offered by James Hamilton of the Amazon Web Services team suggests that once you experience a single memory error, you are 228 times more likely to have another within a month. For this reason, I think ECC memory is mandatory for workstations being used by professionals.

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About the Author: Robert Green

Robert Green

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Re: Specifying CAD Workstations, Demystified
by: Daniel Gijsbers
November 19, 2013 - 8:05am
I always tell people to chose their cpu for their workstation as follows: Almost all Autodesk software is single threaded which means you will not benefit from multiple cores. Take the benchmarks of different processors and divide those by the amount of cores. This means that, at this moment for Autocad that the I7 processors are faster than Xeons.