Introduction

Intel launched the Core i5-8600 six-core processor just a few weeks ago. It wasn't part of last year's first wave of 8th generation Core "Coffee Lake" processors since Intel probably held back the multiplier-locked i5-8600 and i5-8500 to space the price-performance sweetspot product i5-8600K apart from the $190 i5-8400, which was the company's first sub-$200 six-core processor at the time.

The Core i5-8400 did enough to disrupt AMD's first-generation Ryzen 5 series, particularly the Ryzen 5 1600. With the advent of the second-generation Ryzen 5 2600X and 2600, both priced below the i5-8600K, Intel finds the need to bolster its Core i5 "Coffee Lake" series at newer price points, with the i5-8500 and i5-8600. The i5-8500, priced at $199, reaches the psychological 3.00 GHz barrier for its nominal clock (the i5-8400 is clocked at 2.80 GHz), while the i5-8600 ups that with 3.10 GHz. Both are 6-core/6-thread parts with 256 KB of L2 cache per core and 9 MB of shared L3 cache, and both feature Turbo Boost, which spool up clock speeds to over 4 GHz.


The Core i5-8600, which we're reviewing today, is launched at $229, the same price as the Ryzen 5 2600X. It's interesting to note that its max Turbo Boost frequency of 4.30 GHz is the same as that of the i5-8600K even though its nominal clocks are quite far apart (3.10 GHz vs. 3.60 GHz). You lose out on the unlocked multiplier, meaning its not possible to significantly overclock these chips. What's more, unlike the i5-8600K, its TDP is rated at 65W, and Intel is including a stock cooler, so you don't have to buy one, which lowers overall costs.

The target audience for this chip is gamers who don't plan on overclocking their CPU, and who are looking for a processor that strikes a price-performance sweetspot under $250, and which doesn't bottleneck any high-end graphics card. You should ideally be able to pair the most expensive graphics cards and SSDs on the market with this chip to game at the highest resolutions.

This review uses our updated test suite for processors in 2018, which includes the latest BIOS updates with microcode fixes for recent security issues, Windows 10 Fall Creators Update with all updates, and new software tests and games, which are all using the latest versions, too.

A Closer Look

The Intel Core i5-8600 comes in a slightly thicker and heavier box than the i5-8600K because it includes a stock fan-heatsink.


Intel's stock fan-heatsink for the LGA115x sockets hasn't changed much within the past decade, beyond evolving regulatory compliances (becoming lead-free, RoHS, etc.) It's the same top-flow cooler that has a cylindrical heatsink with radially-projecting, forked aluminium ridges, which is ventilated by a 70 mm fan. With its TDP rated at 65W, you should be able to run the i5-8600 with this cooler.


The Core i5-8600 looks like every other LGA115x processor launched within the past decade. A point to note here is that unlike AMD, Intel is using glue and thermal paste as the interface material between the integrated heatspreader and die. Enthusiasts generally prefer soldered dies. Gamers don't care as long as their machines are quiet enough.


With this generation, the biggest point of confusion has been the package. The 8th generation Core desktop processors bear the "LGA 1151" package markings and look like they'll work on older 100-series and 200-series chipset motherboards. They'll even physically fit on them since nobody at Intel bothered to put the key notches elsewhere. The chips, however, will not work on older motherboards. The machine won't even POST. The box clearly states that you need a 300-series chipset motherboard to use the processor.

Architecture

The 8th generation Intel Core processors are based on the "Coffee Lake" micro-architecture. The CPU circuit design is essentially the same as with "Skylake," but the silicon is built on Intel's third iteration of the 14 nanometer silicon fab process, which the company refers to as 14 nm++. This node improves the ability for the chipmaker to dial up clock speeds at minimal power/thermal cost. While the quad-core "Kaby Lake" silicon was "Skylake" built on a refined 14 nm+ process, the six-core "Coffee Lake" silicon is a new design with a die-area of 150 mm².

The "Coffee Lake" silicon physically features six CPU cores with 256 KB of dedicated L2 cache per core and 12 MB of shared L3 cache. On the Core i5 "Coffee Lake" series, the L3 cache is reduced to 9 MB, which still keeps up with the 1.5 MB/core configuration of previous-generation Core i5 chips. The integrated Gen 9.5 graphics core is physically carried over from the "Kaby Lake" die, but is bolstered by higher clocks and an enhanced driver, which lets Intel brand it as the "Intel UHD Graphics 600 series." Internal communication is handled by a "ring bus" and not the mesh-interconnect Intel deployed on its new Core X "Skylake-X" processors.



The system agent (the integrated Northbridge) also appears to be carried over from the "Kaby Lake" die with its dual-channel DDR4 memory interface. There are minor improvements, such as the standard DDR4 memory clock being upped to DDR4-2666 (JEDEC) on the Core i7 and Core i5 SKUs and DDR4-2400 on the Core i3 SKUs. The IMC supports XMP 2.0 profiles. The processor only puts out 16 PCI-Express gen 3.0 lanes meant for PEG (PCI-Express discrete graphics). It talks to the motherboard chipset over the DMI 3.0 chipset bus, with a 32 Gbps-per-direction bandwidth.



The "Coffee Lake" CPU core is of the same exact design as Skylake and Kaby Lake, which dates back to 2015. Compared to the Haswell/Broadwell core, it features an improved front-end with a 25% fatter 5 µOP pipeline, a 50% wider allocation queue depth; an improved branch-prediction unit, and a wider instruction window. The execution stage features a slightly bigger re-order buffer, a bigger integer register file, an improved on-chip memory system. All of these contribute to a 5-10 percent IPC increase over "Haswell" to "Skylake" clock-for-clock.



Between "Skylake" and "Coffee Lake," Intel turned its R&D efforts toward refining the 14 nm process. It met with success on "Kaby Lake," and owing to its significantly higher clock speeds, "Kaby Lake" was able to provide higher performance than "Skylake." With "Coffee Lake," the nominal clock speeds look low, but Turbo Boost frequencies are higher than with "Kaby Lake," and refinements in the process allow the chip to sustain elevated boost-clock states better. As we mentioned throughout the introduction, the design focus of these chips is to increase core counts across the board in order to better compete with AMD Ryzen.

The Gen 9.5 integrated graphics core takes up nearly a third of the die area. Since it's of the same core configuration as the one on the "Kaby Lake" silicon, it still features 24 execution units in the GT2 trim (featured on the i7-8700K). Higher clocks and some driver magic let Intel brand it "UHD Graphics." Don't expect to play PUBG at 4K on this, the "UHD" moniker only indicates that the IGP can handle 4K Ultra HD displays, features modern connectivity options such as DP 1.4 and HDMI 2.0, and can playback 4K video in new formats with 10-bpc color and HDR10/Dolby Vision standards.

Intel 300-series Platform

Chipset options for the Core i5-8600 include the top-end Z370 Express which the platform debuted with, followed by the H370 Express, the B360 Express, and the entry-level H310 Express. The Z370 Express chipset, which succeeds the Z270 Express, appears to carry over the same platform feature set. It wouldn't surprise us if the Z370 turns out to be a re-brand of the Z270; however, we have no way of telling right now. The H370 has almost all features of the Z370, but one lesser M.2 slot, lack of CPU overclocking support, and lack of multi-GPU support. The B360 Express has fewer M.2 slots still. As we mentioned on the previous page, 8th generation Core processors won't work on 100-series/200-series chipset motherboards.