Intel Core i7-8700K And Core i5-8400 Review: Coffee Lake - More Cores, Performance And Value

Intel Core i7-8700K And i5-8400 - Setup, SANDRA, And PCMark

Test System Configuration Notes: When configuring our test systems for this article, we first made sure all firmware was up to date, then we entered their respective system BIOSes / UEFI and set each board to its "Optimized" or "High performance" defaults. We then saved the settings, re-entered the BIOS and set the memory frequency to the maximum officially supported speed for the given platform (without overclocking). The SSDs were then formatted, and the latest build of Windows 10 Pro x64 was installed.

chip in socket
Intel Core i7-8700K In the Gigabyte Aorus Z370 Gaming Ultra

When the Windows installation was complete, we fully updated the OS, and installed all of the drivers necessary for our components. Auto-Updating and Windows Defender were then disabled, and we installed all of our benchmarking software, performed a disk clean-up, and cleared any temp and prefetch data. Finally, we enabled Windows Quiet Hours and let the systems reach an idle state before invoking a test.  Also note, that to ensure AMD's SenseMI technology was performing to its full potential, the Ryzen-powered systems used Windows' High Performance mode or AMD's optimized Ryzen Balanced power profile.

HotHardware's Test Systems
Intel and AMD - Head To Head
test machines
Preliminary Testing with SiSoft SANDRA 2017
Synthetic Benchmarks

We began our testing with the latest version of SiSoftware's SANDRA 2017, the System ANalyzer, Diagnostic and Reporting Assistant. We ran four of the built-in sub-system tests that partially comprise the suite with Intel's latest processors (CPU Arithmetic, Multimedia, Cache and Memory, and Memory Bandwidth). All of the scores reported below were taken with the CPUs running at their default settings, with 16GB of DDR4 RAM running at 2666MHz, in-channel mode Gigabyte Aorus XZ370 Gaming Ultra motherboard.

8700 san cpu
Processor Arithmetic - Core i7-8700K

8700 san mce
Multi-Core Efficiency - Core i7-8700K

8700 san mem
Memory Bandwidth - Core i7-8700K

8700 san cache
Cache and Memory - Core i7-8700K

8400 san cpu
Processor Arithmetic - Core i5-8400

8400 san mce
Multi-Core Efficiency - Core i5-8400

8400 san mem
Memory Bandwidth - Core i5-8400

8400 san cache
Cache and Memory - Core i5-8400

Relative to Intel's previous generation products, the two additional cores available on the Core i7-8700K and Core i5-8400 propel them out to big leads in the processor arithmetic tests over previous-gen processors in the same segment -- over 238GOPS with the 8700K. Memory bandwidth is in the 23GB/s range (give or take) and latency and core-efficiency are all in-line with Kaby Lake-based processors.

PCMark 8 v2
System Level Benchmark

PCMark 8 v2 is one of Futuremark’s series of popular PC benchmarking tools. It is designed to test the performance of all types of systems, from tablets to desktops. PCMark 8 offers five separate benchmark tests -- in addition to battery life testing -- to help consumers find devices that offers the perfect combination of efficiency and performance for their particular use case.

This latest version of the suite improves the Home, Creative, and Work benchmarks with new tests using popular open source applications for image processing, video editing, and spreadsheets. A wide variety of workloads have also been added to the Work benchmark to better reflect the way PCs are used in enterprise environments. These tests can be run with or without OpenCL acceleration. We chose to run with OpenCL acceleration enabled to leverage all of the platforms’ available CPU and GPU compute resources…


The additional pair of latest-generation cores and its relatively high frequencies push the Core i7-8700K into the lead on PCMark. The Core i5-8400 performed very well here too. Some of the tests that comprise this suite are not multi-threaded, hence the many-core processors sometimes trailing.

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