Intel Coffee Lake i7-8700K & i5-8400 Review

by Michael "SKYMTL" Hoenig     |     October 4, 2017

The Z370 Platform; More of the Same or Just Enough?

Letís get this straightened out right away: Coffee Lake processors will require you to buy a new motherboard. Previous generation Kaby Lake processors wonít be forwards compatible with these new boards either. Should you be shocked, dismayed or outraged? Some folks will go through each of those stages because from a chipset feature standpoint, thereís absolutely nothing noteworthy to distinguish Z370 from its predecessors. All of the improvements in this particular generation stem from improved power delivery and support for higher memory speeds.

And yet if we take emotion out of this equation, there may very well be some justifiable reasons for this switch according to Intel. There are some very specific memory trace requirements for consistent memory 2666MHz operation. Those improvements should also make this particular platform a record setter when it comes to achievable memory speeds since they will directly improve stability above 3600MHz. Power distribution for Coffee Lake processors has also seen an evolution but only in an incremental way, and mostly to support the new 6-core, 12-thread variants.

We also canít forget that people upgrading to 8th generation Intel processors likely wonít be doing so from Kaby Lakeís Z270 or even Skylakeís Z170 platform. Rather, they are Sandy Bridge, Ivy Bridge and even Broadwell users who are finally able to break with the 4-core, 8-thread architectural rut that has been around for the better part of seven years. They no longer need to look towards the premium HEDT space to for the ability to concurrently process more threads. Access to features like M.2, USB 3.1 Gen2, Thunderbolt and support for NVMe storage devices is just icing on the cake and will bring their systems up to current standards.

The first thing that you need to understand about Z370 is that Intel has tried to pull a bit of a fast one in their marketing materials. Instead of listing PCIe 3.0 lanes that originate from the CPU (thereís still only 16 in this case), they now list a more nebulous and extremely misleading ďPlatform PCIe 3.0Ē lanes which combines Coffee Lakeís 16 lanes with the chipsetís 24 to make a total of 40.

Much like with Z270 there are 24 PCIe lanes, of which four are dedicated towards a high speed interconnect for Optane or other NVMe storage devices. None of these lanes can actually be utilized for graphics duties and indeed many of them will be given over to interfaces like USB 3.1 Gen2, Thunderbolt and even U.2 or switched over for additional SATA / USB interconnects. Honestly, there are absolutely no differences here when compared to Z270 but motherboard vendors may endeavor to differentiate their Z370 boards with different layouts for key interfaces. More on that later.

Now moving up to the processor itself and as I alluded to before, there arenít really any changes here either since the architecture itself hasnít been given any fundamental updates. Unlike Ryzen processors which include an additional four Gen3 lanes explicitly for high bandwidth storage and four native USB 3.1 Gen1 outputs directly on-die, Intel only has their usual 16x lanes which can be split into two x8 interfaces. Thatís it.

But how are motherboard vendors endeavoring to differentiate their Z370 products from those launched less than a year ago? Letís take a look at the ASUS RoG STRIX Z370-E Gaming for some pointers.

Physically, there arenít any major operational differences between the two boards; they have the exact same PCIe slot layout and VRM heatsink design. Even the sound solutions are identical. All in all it looks like other than a few tracing changes, they are carbon copies of one another.

There is however one relatively significant addition to the Z370 version: gone is the little dinky heatsink over the chipset and in its place is a more extensive affair which also covers the lowermost (primary) M.2 slot. As faster NVMe storage devices make their way to market vendors have increasingly realized that more cooling is needed for these small yet hot-running drives. There were times when some SSDs ended up throttling due to heat load on their controllers. Hence, we will see more M.2 heatsinks make their way onto this generation of motherboards.

The way Z370 handles NVMe and SATA storage is interesting since it natively supports just a single device, in this case itís that bottom M.2_1 slot which also shares bandwidth with the SATA_1 port. Meanwhile ASUS has added a second M.2 connector which I conveniently labeled M.2_2 and utilizes a PCIe switch (in this case ASMediaís 1490) while sharing bandwidth with the SATA_5 and SATA_6 ports. Basically this shared bandwidth means if you use one of those connectors, the other will be disabled. Note however that M.2_2 only supports NVMe devices and doesnít have SATA compatibility.

M.2 RAID isnít supported here, nor are there any plans to add that feature in the future since it is reserved for Intelís X299 platform.

Since Intelís Z370 doesnít have any native support for USB 3.1 Gen2 or the newest iterations of Thunderbolt, those have to be added via secondary controllers attached to the chipsetís PCIe 3.0 ports. In the STRIXís case thereís an onboard front panel Gen2 connector which Ėif utilized- disables the boardís PCIE_2 and PCIE_4 slots since it requires a pair of dedicated lanes. This runs off of an ASM 3142 controller.

The backplate also has two USB 3.1 Gen2 connectors (one Type-A and one Type-C) which have a pair dedicated PCIe 3.0 lanes running into a single ASM 3142. While these donít share bandwidth with any other onboard items, they do feed off of the same internal port which means bandwidth will be partitioned if two Gen2 devices are being used at the same time.

If you are running multiple high bandwidth drives and connected devices, there are indeed some sacrifices that still need to be made for Z370 users but they are tempered by the fact this platform costs significantly less than X299. There are other tangible benefits as well, some of which are well highlighted by ASUS here.

When it comes to memory overclocking, the Z370 STRIX-E now has an additional ďgearĒ of 4000MHz whereas its predecessor officially topped out at 3866MHz. More importantly, that 4000MHz can be achieved with four DIMMS and 64GB provided your CPUís memory controllers can handle the load.

Finally there are those minor modifications I talked about, the ones that wonít make any headlines but ASUS nonetheless decided to include here. The Bluetooth 4.2 protocol is now being used (versus 4.1 for the Z270 STRIX), thereís a new addressable RGB header and I even noticed a fan header dedicated to the M.2 slot. But do these items make this particular board a viable solution for would-be Coffee Lake buyers? Iíd say so considering its price will likely be just under $199 USD.

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