Intel Core i5 8400 Linux Performance

Today marks the embargo expiry for reviews on Intel's new Coffeelake desktop processors. While a CPU refresh may not normally be too exciting, thanks to the pressure from AMD with their Ryzen processors pushing core counts higher, Intel is now upping the core counts in their desktop CPUs. Today we will be featuring Linux benchmarks of the Core i5 8400 and Core i7 8700K while this article is focusing on the i5-8400: a six-core Core i5!

Core i5 processors have traditionally been quad-core CPUs without Hyper Threading. With Coffee Lake, the Core i5 parts are now at six cores. Core i7 CPUs are also up to six cores while having Hyper Threading to yield 12 threads. The Core i3 Coffeelake processors meanwhile are four core, compared to previous generations being dual-core. Also practical is the complete Coffee Lake line-up now supports dual channel DDR4-2666 memory natively.

The Core i5 8400 processor being benchmarked in this article has its six cores clocked at 2.8GHz while having a single-core boost frequency of 4.0GHz or 3.8GHz boost across its six cores. The i5-8400 has a 9MB L3 cache size and has a 65 Watt TDP while its MSRP is $182 USD.

Compared to the non-refreshed Kabylake Core i5 7400, the Core i5 8400 has the two extra CPU cores, slightly lower base frequency of 2.8GHz vs. 3.0GHz, but a higher turbo frequency of up to 3.8GHz rather than 3.5GHz. There's also 3MB more of the L3 / Smart Cache and the native DDR4-2666 support rather than DDR4-2133.

The Core i5 8400 sits in price between the Ryzen 5 1500X and Ryzen 5 1600. The Ryzen 5 1500X has four physical cores plus SMT, 3.5GHz base clock, 3.7GHz turbo frequency, and 16MB L3 cache. The Ryzen 5 1600 meanwhile is a six-core part like the Core i5 Coffee Lake CPUs but with SMT to yield 12 threads, 3.2GHz base clock, and 3.6GHz turbo clock while having a 65 Watt TDP.

Thanks to ASUS for providing the PRIME Z370-A motherboard for our Coffee Lake launch-day benchmarks. More on that motherboard is covered in the i7-8700K and will be featured in its own review shortly on Phoronix.

More Coffee Lake details in general can be found in our just-published Core i7 8700K Linux review. The CPUs being tested for this lower-end-focused comparison (some different CPUs as well from that i7-8700K review) include the:

- Core i3 7100
- Core i5 4670
- Core i5 6500
- Core i5 7600K
- Core i5 8400
- Core i7 4790K
- Core i7 7700K
- Core i7 8700K
- Ryzen 3 1200
- Ryzen 3 1300X
- Ryzen 7 1700
- Ryzen 7 1800X

Due to having a Z370 motherboard for just two days, our Coffee Lake Linux benchmarks today are a bit brief but plenty more tests are being worked on for publishing in the days ahead. All of these systems were tested with Ubuntu 17.10 using the Linux 4.13 kernel, GCC 7.2 compiler, and switching to the performance CPU frequency scaling governor. The Core i5 8400 system was tested with dual-channel 2 x 8GB Corsair DDR4-3200 memory (as were the other DDR4 systems), NVMe SSD storage, and was using the ASUS PRIME Z370-A motherboard for these Coffee Lake benchmarks.

As mentioned in the Core i7 8700K, the only Linux issue we have experienced so far with Coffee Lake is over the i915 DRM driver appearing to have issues with the UHD Graphics 630. Stay tuned for benchmarks likely later today or tomorrow about the Coffee Lake graphics on Linux. (Update: With Linux 4.13~4.14, you need to set i915.alpha_support=1 to enable this "alpha" quality driver support for Coffee Lake.) In terms of the CPU functionality, it's been working fine with the tests thus far this week using Ubuntu 17.10.

All of these Intel/AMD Linux CPU benchmarks were facilitated in a fully-automated and standardized manner using the Phoronix Test Suite.