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

Cooling & Temperature

Power Consumption In Detail

At idle, the differences in power consumption between Intel's CPUs are fairly marginal. All of them end up just about where we'd expect.

AMD's Ryzen processors draw significantly more power because their idle clock rates are higher.

Core i5-8400's average power consumption in applications that combine 2D and 3D loads (like AutoCAD) is in line with the performance we observed.

Gaming paints a more balanced, but very similar picture.

Intel's Core i5-8400 falls squarely within its TDP class.

The finishing order changes dramatically once we fire up an AVX-heavy stress test with all cores running at their top Turbo Boost bins.

This benchmark breaks Intel's rated TDP if the motherboard doesn't quickly rein in power consumption. Otherwise, Core i5-8400 hits values ​​well above its thermal design power, as illustrated in our chart.


Core i5-8400 can easily be cooled by a heat sink/fan or compact closed-loop liquid cooler, despite Intel's continued use of thermal paste between the die and heat spreader.

Pricier thermal solutions offer little advantage in cooling Core i5-8400. This is illustrated by the high delta between Intel's die and IHS, which results from that thermal paste the company uses.

The Core i5-8400 is relatively easy to cool, even with a standard heat sink and fan.


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Paul Alcorn

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