Specifying CAD Workstations, Demystified13 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.
Could you explain how Intel Integrated Data Direct I/O (DDIO) works with the processor cache?
Intel Data Direct I/O is a very cool technology and is only available on the Intel Xeon processor E5-1600/2600v2 product family–based workstations. Here is a simple way to understand how it works: Imagine you are working on something and I repeatedly ask you for a pencil. You would need to stop working to get me the pencil, right? That interruption of workflow is what Intel Data Direct I/O helps to prevent. It allows the CPU do what it was designed to do — process data and not be interrupted by I/O tasks. Intel DDIO makes the processor cache the primary destination and source of I/O data rather than main memory, helping to deliver increased bandwidth, lower latency, and reduced power consumption.
Now that SATA 3.0 disk controllers and solid-state drives (SSDs) are becoming standard, will new technologies pay off even more?
I love SSDs, and CAD users should too. Let me share a story with you. We provided CATI, a Chicago-based SolidWorks reseller, with some SSDs to understand what the potential impact might be on a typical day in the life of a user. What we learned from them was that SSDs attached to SATA 3.0 controllers improved their throughput by as much as 56%. No matter who you are, there are only 60 minutes in an hour — no more, no less. If your workstation could process 56% more data, can you afford not to make that investment?
More hardware vendors are now equipping CAD workstations with smaller, low-cost SSD cache drives that work in tandem with a traditional hard drive. How does this compare, performance-wise, with a large SSD primary drive?
As I said, SSDs are great, but they are expensive. We realize not everyone can afford an all-SSD-based workstation. That is why we created technologies like Intel Smart Response Technology or Intel CAS-W (cache accelerated storage for workstations) — to get SSD-like performance and lower-cost storage. But SSD-like performance is limited to the size of the SSD cache drive, so if your software needs more drive space than the drive's size, you'll slow down to the speed of your hard drive.
Solid-state drives look like regular hard drives from the outside,
but are constructed of memory chips rather than spinning mechanical disks.
Can you give a brief explanation of Intel Smart Response Technology and Advanced Vector Extension technologies and what they can do for CAD users who have very large data and processing tasks?
Intel Smart Response Technology enables SSD-like performance with the benefits of inexpensive HDD capacity. SRT allows you to set an SSD maximum cache size to 64 GB, allowing it to function like an actual cache. Rather than caching individual files, Intel focuses on frequently accessed logical block addresses (LBAs). The result can be improved performance. I still like SSD-based workstations for maximum speed, though.
AVX2 and AVX-512 are very cool software technologies available on all Intel Xeon–based processors. They can play a significant role in the performance of applications such as photorealistic imaging and simulation. AVX-512 enables processing of twice the number of data elements that AVX/AVX2 can process with a single instruction cycle — which obviously leads to improved performance.
Is there a rule of thumb for how to configure a CAD workstation to get the best bang for your buck?
Let me start by saying one word: balance. Don't over- or under-invest in the key technologies that make up a workstation.
Here are my simple rules:
- Buy one processor down from the top; clock speed is king with CAD!
- Use the savings from buying the second-fastest processor available to invest in RAM, as we discussed earlier.
- Most CAD users really don't need a high-end graphics card, but they probably need more than an entry-level card, so invest in a $300 midrange option.
- Take your savings from buying the right graphics card and invest in an SSD.
One more point on balance: It means invest in all the things your engineers do and not just one type of task. What I just described is a very balanced system. Yes, it will cost you slightly more, but it will also help you optimize your throughput and get more done in a day.
Thanks so much for agreeing to this interview, Wes. This is great information for my readers!
I really appreciate the opportunity to share some insights I have picked up through the years — all 33 of them. One of the most important points I can leave with your readers is that balance seems to be the best way to optimize a workstation to deliver a highly productive solution that can impact all the things CAD power users do in a day.
Second, don't skimp on investing in your CAD power users. Think of it this way: You are already in investing $50,000 or $80,000 annually in this professional, so why skimp on his or her workstation? Let's assume a balanced workstation costs $1,500 to $2,000 more than what you were thinking of investing; imagine that for $10 to $13 per week you could have potentially increased your user's throughput by more than five times. If you don’t believe me, then read the CATI study.
Finally, do you see any trends in hardware configuration that we should keep our eyes on?
Hmm, what does the future hold? More cores, more computing power, and more bandwidth.
I hope you've found Wes Shimanek's insights useful, and that you'll use this information to support your request for better-equipped workstations in your next budget. In the next edition of the CAD Manager's Newsletter, I'll be sharing my impressions of Autodesk University and providing my year-end forecast for CAD managers. Until then.
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