Herrera on Hardware:

CPU Boost & Base Clocks

Testing CPUs for CAD, Part 2

By Alex Herrera

In last month’s installment, we took a deeper look at the engineering tradeoffs that shape modern high-performance CPUs. Realities in physics and engineering mean that one choice in CPU design — for example core count — has varying and sometimes counter-intuitive impacts on the other critical performance metrics, such as base and boost frequencies. This month, we pick up where we left off, ready with test platforms — two systems (the BOXX Apexx A3 Denali and Puget Systems' X570-E) and three Ryzen 5000 SKUs — to validate (or not) the expected impact in both the multi-thread and single-thread (1T) workloads common in CAD workflows. On top of the 8C Ryzen 5800X and the 16C 5950X shipped in the the two systems, we also swapped in a third CPU to compare, a 12C 5900X provided courtesy of AMD. See the breakdown of these systems below.

Specifications for the test systems.

More Cores Can Yield Higher Performance, but Not with Every Job

Let’s kick off the test results with the obvious case, comparing multi-threaded performance as core counts rise.

The results running the SPECworkstation 3.0.4 Product Development Suite on the two systems and three Ryzen 5000 CPUs (normalized to the Ryzen 7 5800X on the BOXX Apexx A3 Denali).

As shown by the results (above) running the SPECworkstation 3.0.4 Product Development test suite, representing multi-threaded workloads common to CAD workflows, the SKUs with more cores provided higher performance. The improved performance is consistent, moving up from the 8C (eight core) AMD Ryzen 7 5800X up to the 16C AMD Ryzen 9 5950X, with the Ryzen 9 5950X outperforming the Ryzen 7 5800X by 54% (and that’s with Ryzen 7 using the air-cooled system and the Ryzen 9 using liquid-cooled).

The gains for the higher core count SKUs come despite some decline in the work completed per core, which declines to some degree, based on that lower base frequency and conflicts in sharing system level resources, such as L3 cache, external memory, storage, and graphics.

Still, the conclusion is clear: if your CAD work is dominated by multi-threaded workloads — such as simulation and rendering, then you should be more concerned about having more cores in your workstation, regardless of how much the base clock drops.

Comparing Single-Thread (1T) Performance for CAD Modeling

The higher-core count Ryzen 5950X besting the two lower-core count Ryzen 5000s on multi-thread capable workloads is not a surprise, despite the former’s lower base clock. The more interesting analysis, and the primary motivation behind this testing exercise, is to compare the single-thread performance as a function of base and boost clocks for our three Ryzen 5000 SKUs. Secondarily, we want to find out how much liquid-cooling might help in a nominally clocked system (ie., not overclocked).

The tests we ran included Cinebench R20 and four components of PassMark Software's Performance Test 10, the latter selected for their particular relevance in CAD workflows: physics, compression, and floating-point. All five were run with systems constrained to execute only one thread at a time. The first, albeit not surprising, take-away is the tight grouping of the results. It’s fair to ask, why you would want to weigh such differences when they’re so small, with no more than a 4% range across tests and SKUs (normalized to the 8C, liquid-cooled AMD Ryzen 7 5800X). Hold that thought though, until we look at how boost spec is defined.

More than assessing the magnitude of the differences, this analysis determines which CPUs under which type of cooling performed the best on 1T workloads.

Specifically, did it track base frequency or boost frequency? And, if more closely tracking boost frequency, did the increased efficacy of a liquid-cooled system appear to help the CPU maintain a higher boost for longer amounts of time? Find out more!  Read more »

Alex Herrera is a consultant focusing on high-performance graphics and workstations.

FROM OUR SPONSORS:

Inspiring the Next Generation of Engineers

Bentley Systems introduces its new educational program designed to excite and inspire students of all ages and encourage them to discover their inner engineer.

Bentley Systems recently introduced its new Bentley Education Program, a sweeping educational program that encourages students to investigate engineering and infrastructure as a career, plus grants students no cost access to Bentley applications with specialized tutorials for each program. 

Cadalyst met with Bentley Systems’ Chief Success Officer, SVP Katriona Lord-Levins, and Vice President of Bentley Education Vinayak Trivedi, recently to learn more about this new program, why the company spearheaded it, and how they hope to inspire a new generation of engineers from all walks of life.

When asked why the company chose now to introduce its educational program, Lord-Levins and Trivedi offered a variety of reasons, but the most important one is the reality that the industry as a whole is seeing a need for talent within the engineering career pipeline. With that as its underpinning, Bentley strives also to:

• address the industrywide problem of the increasing digital skill gaps and the widening disconnect between industry and academia;
• remove the barrier of technology adoption by making it easy for students and schools to use Bentley software at no cost;
• help students learn critical digital skills to support the talent pipeline and bolster infrastructure growth worldwide; and
• help students who are already interested in infrastructure get a jump-start on their career.               

Bentley Systems wants to inspire and encourage students to think about infrastructure engineering as a career path and expose young minds to the vast field of the industry opportunities that are ahead of them. Bringing the technology to the students, so that they can get excited about engineering is key. Bentley is using social media, including YouTube to get in front of their audience, and is introducing the Future Infrastructure Star Challenge, a new competition that allows students to dig deeply into the software and potentially win cash prizes, plus spend time with top designers to help bring their designs to life. Read more »

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