Intel Xeon W-3975X Review: 28 cores of blistering performance

Credit: Gordon Mah Ung

Intel’s crazy-ass 28-core Xeon W-3175X isn’t a CPU built for you, me, or most of us.

Sure, Intel pitches it as a high-end workhorse: “Built for handling heavily threaded applications and tasks, the Intel Xeon W-3175X delivers uncompromising single and all-core world class performance for the most advanced professional creators and their demanding workloads.” 

But make no mistake, the 28-core Xeon W-3175X is a chip made to do one thing: make waves and push back at an increasingly assertive AMD. And it delivers—for a pretty penny. Fasten your seat belts, because you’re about to see some huge motherboards, a huger number of benchmarks, and the hugest desktop CPU price ever. 

Gordon Mah Ung

What is Xeon W-3175X?

If you’ve read reviews of Intel’s previous 18-core Core i9-7980X or 18-core Core i9-9980X that replaced it, you already know something about the Xeon W-3175X. Like them, it’s essentially a Skylake-SP aimed at a high-performance crowd. It’s built on a 14nm process and has a stock TDP of 255 watts. To keep its cores fed, it features support for six channels of DDR4 memory in ECC or non-ECC trim.

Perhaps its most important feature may be its unlocked status. As always, Intel doesn’t actually condone overclocking, the same way Lamborghini doesn’t tell you to break local speed limit laws.

What's in the name? Why isn’t this a Core i9? Or, maybe a Core i11? Intel didn’t say why it chose to keep the Xeon name, but in the end it doesn’t matter much. With a list price of $3,000, t’s how it performs that matters.

Gordon Mah Ung

Crazy-powerful motherboards

One look at the first two motherboards designed for Xeon, and you know this isn’t for someone to run a SQL database to manage the inventory for a supermarket. Gigabyte’s AX1 features nothing less than a 28-phase power circuit for the new Xeon W-3175X. 

Hell, the Asus Xeon W-3175X motherboard weighs 10 pounds alone. Like the AX1 it, has enough auxiliary power connectors to light up a small city.

You don’t need two 1,600-watt power supplies to run a few virtual machines. No, the only time you’d need that amount of power is for over-the-top overclocking. Yes, it's benchmark time. 

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How we tested

For our tests, we basically made quad-core and eight-core CPUs leave the building. What? Just 18 cores? Get out! No, for this slug fest we wanted to find out the eternal question of what would happen if The Hulk fought Superman. Yes, nerds, you want to only know what happens when 28-core Xeon W-3175X faces off against 32-core Ryzen Threadripper 2990WX.

For our tests, we used the same configuration as our original Ryzen Threadripper 2990WX review here.  The only variance from the original review were updated motherboard drivers, updated GPU drivers and an updated BIOS and the latest version of Microsoft Windows 10 Pro RS5. While we used the same GPU, storage and OS for both, we did vary on memory and cooling.

Gordon Mah Ung

The Threadripper 2990WX ran in quad-channel configuration with 32GB of dual-rank, DDR4/3200. The Xeon W-3175X, ran 48GB of ECC DDR4/2667in hexa-channel configuration.

For cooling, the Threadripper 2990WX used the same Enermax TR4 CLC cooler, while the Xeon W-3175X was cooled with an Asetek 690LX-PN.

The motherboard for the Xeon W-3175X was Gigabyte’s soon-to-be-released AX1, ,while the Threadripper used the same MSI X399 MEG from the original review.

One last note before we get too far: Since our last review, AMD released its “Dynamic Local Mode,” which helps keep threads on the most efficient cores in the CPU rather than let Windows randomly throw them at the wall. Normally DLM works really well, but there were moments when it slightly hurt performance. Because you have to enable DLM through Ryzen Master, we opted to run both DLM and the default configuration for our tests.

Finally, all of the tests were run at “stock clock” which oddly, means many things to many people these days. Basically, it’s the default setting on both boards. 

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Xeon W-3175X 3D Modelling Performance

Sometimes we apologize for using 3D modelling tests for performance testing because it’s not really what most people are doing. Well, if you buy a 28-core Xeon or a 32-core Threadripper 3D rendering is probably your jam.

The first result is from Maxon’s Cinebench R15. Although it uses a somewhat older version of the engine than the one in its Cinema4D product, it scales with core count and thread count exceptionally well. More cores typically mean more performance 

The clear winner here is the Xeon W-3175X, which crosses the finish line about 10 percent ahead of the Threadripper 2990WX. Some will see the proximity of the AMD CPU (as you can see, turning on AMD’s dynamic local mode slightly depresses performance) and think it’s a tie—but you should remember that we are talking about 64 threads vs. 56 threads. We had expected the Threadripper 2990WX to take the win here instead of losing it.

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The Threadripper’s loss to the Xeon isn’t just in Cinebench. In the Persistence of Vision ray tracer, the 32-core chip loses to the 28-core chip by about 8 percent. Again, DLM slightly depresses its performance.

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Where it gets particularly ugly for Threadripper is in the Corona 1.3 Render. The Corona Renderer is an “unbiased photo-bought realistic renderer.”
Unbiased” refers to its rendering technique—not an allusion to any hardware leanings. The test embraces multi-core CPUs, so we expected iThreadripper would do better than Xeon. Nope: t to be similar to the Cinebench performance but the Xeon absolutely hammers the Threadripper to the tune of 28 percent.

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Next up is the Chaos Group’s V-Ray renderer. Generally, the more cores you throw at it, the faster it gets. And yet the Xeon W-3175X again whups the Threadripper, despite the latter’s advantage in thread count. Possible reasons include each CPU’s particular micro-architecture design, the actual clock speeds each CPU runs at when loaded up, to the compiler used for each. We’ll try to circle back to find out more. 

All that is academic, though. if the only thing that matters to you is less waiting for your V-Ray or Corona-based render to finish.

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Not everything is that ugly though. Using the latest beta version of Blender and Mike Pan’s BMW model, the Xeon again wins, but by just 5 percent. It’s close enough to be boring, unless, of course, you’re wondering why the extra 8 threads in Threadripper aren’t pulling their weight.

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Our last multi-threaded rendering result is Blender’s new benchmark. It smashes together multiple popular benchmark models, runs them against Blender, and spits out a final result based on how long it took. There’s the option to run it against the GPU or the CPU, so we opted for the CPU test.

The result, again puts the 28-core Xeon on top by about 6 percent. Again, not a huge win, but it’s doing it against a 32-core CPU.

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Want to see how it performs in mainstream apps? Keep reading to find out.