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Intel Core i5-8400 Review: Six Cores On A Budget

CPU Computing & Rendering Performance

CPU Performance: Workstation

Many modern suites include modules that are based exclusively on computing and simulations. This means we need to go beyond just 3D workstation performance. However, software packages like SolidWorks don’t scale perfectly based on core/thread count. Consequently, even quad-core processors keep up if they run at high-enough frequencies and support SMT.

This is also seen in a direct comparison between the Core i5-7600K and Core i5-8400. The latter does not benefit much from its extra cores and larger aggregate cache.

Frequency is all that counts in Creo 3.0. Compared to Intel's Core i5-7600K, the company's -8400 only derives small advantages from its two additional cores.

Clock rate and core count both matter in 3ds Max 2015, so the Core i5-8400 lands slightly behind Intel's Core i5-8600K.

Though an overclocked Ryzen 5 1600X is close on Coffee Lake's heels, the -8400 costs less and facilitates higher performance.

The CPU Composite benchmark makes extensive use of rendering, though, so AMD's Ryzen 5 appears much stronger. Now it's an overclocked 1500X going up against (and beating) Core i5-8400. A lack of Hyper-Threading support likely hurts Intel here.

CPU Performance: Photorealistic rendering

Final rendering doesn’t require a CPU that's good at everything. Rather, this task wants efficiency and fast parallel computation.

When it comes to pure rendering, the Core i5-8400 offers best-in-class performance. It is only challenged by AMD's pricier Ryzen 5 1600X.

The console variant of LuxRender confirms that none of Intel's Core i5s can compete with the Ryzen 5 1600X, stock or overclocked.

Last, but not least, we take a look at Blender in several different workloads.

The first one, with a sample size of 200 pixels, confirms what we saw in the preceding benchmarks: Core i5-8400 trails the Ryzen 5 1600X by a big margin. In fact, a stock 1600X has little trouble beating the Core i5-8600K by more than 20%.

The results obtained from SPECwpc’s Blender loop look similar, even though this benchmark presents a somewhat different task consisting of more than just rendering. Ryzen 5 takes a big lead over Core i5.

The Core i5-8600K pushes upwards as the amount of pure rendering decreases. The rest of the results look similar, though, and Core i5-8400 suffers from its lack of Hyper-Threading.

This trend intensifies as our benchmark incorporates tasks other than photorealistic rendering. Core count isn't the sole determiner of performance; IPC throughput factors in as well. The Core i5-8600K even leads, followed by Intel's Core i5-8400.

Ryzen 5 1600X jumps to the front once again. Core count matters, of course, but operating frequency is also a critical variable.

Intel’s Core i5-8400 offers acceptable performance in semi-professional applications, so it's more than just a gaming CPU. However, the Core i5 series lacks Hyper-Threading support, which is apparent in highly parallelized workloads. Those tasks tend to favor AMD's Ryzen chips.

Then again, this throws the potent six-core chips right where Intel wants them. If they fared too well, Core i5 would cannibalize sales of the pricier Core i7s.


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Paul Alcorn is the Deputy Managing Editor for Tom's Hardware US. He writes news and reviews on CPUs, storage and enterprise hardware.