Intel Coffee Lake

Despite the huge changes in the number of cores in Intel’s latest mainstream CPUline-up this time around,with core boosts for everyCore i3, Core i5 and Core i7 desktop CPU,Coffee Lake offers comparatively little in the way of architecture change so rchipset improvements. The biggest talking point is that Coffee Lake CPUs aren’t backwards compatible with previous LGA1151 sockets. In other words, if you own a Z170 or Z270 motherboard, you’re out of luck if you want to drop a Core i7-8700K into your motherboard.

No backwards compatibility 

Similarly, older CPUs aren’t compatible with the new Z370 motherboards either, and this situation has caused afair bit of commotion among enthusiasts due to the fact that the sockets are practically identical. Both sockets have 1,151 pins, the notches are in the same place and Kaby Lake CPUs will even physically fit into the new socket. However, you’ll be met with failed boots and black screens if you try. 

The close proximity of the January 2017 launch of Kaby Lake and October 2017 Coffee Lake launch, along with the physically identical socket, result edin many people incorrectly assuming that Coffee Lake would be backwards compatible. As it turns out, Kaby Lake is the last CPU core architecture to landon Z270,which means that anyone who invested in a Z270 motherboard recently can understandably feel a little short-changed. 

Sadly, it’s not a situation that can be altered with a simple BIOS update fix either. With their additional CPU cores,Coffee Lake CPUs require extra power, and this power is being fed through numerous activated pins in the CPU socket that were previously dormant. As a result, the pin assignment of the LGA1151 socket has changed,making it incompatible with older CPUs. 

Additionally, in a recent interview with bit-tech, Asus revealed that it’s technically possible for a Z270 board to support a Coffee Lake CPU, but that it would require an upgrade to the management engine, as well as BIOS update. According to Asus, however, Intel has locked down compatibility. The company also hinted that the tweaked socket’s new power-delivery capabilities  might also be useful for CPUs with more cores in the future.

Small change 

Meanwhile, the integrated graphics remains the same under the hood, except for a small bump in clock speed and a name change to UHD Graphics. The chipset doesn’t have any major changes either, and despite some early rumours pointing at more PCI-E lanes, Z370 actually has the same number of lanes as Z270, with 16 lanes for graphics cards. 

Coffee Lake CPUs are all manufactured on a 14nm process, and while that’s technically the same node size as Kaby Lake, Sky lake and Broad well, Intel now calls the process 14nm++ to highlight thef act that the process has been refined three times.This refinement usually means we can expect higher clock frequencies and perhaps even better over clocking too,while Intel in theory has better yields. The down side, is that we now haven’t had a mainstream CPU die shrink for four generations. 

As well as core boosts across the range, The Z370 chipset’s capabilities are practically identical to those of its predecessor with all Core i3 desktop CPUs now sporting four cores,Core i5 CPUs sporting six cores and Core i7 CPUs offering six cores and Hyper-Threading, the L3 cache amounts have also increased. The Core i7-8700K has a hefty 12MB of L3 cache, the Corei5-8600K has 9MB and the Corei3-8350K has 6MB. The latter is particularly interesting, since it means that this £160(inc VAT) processor now has an almost identical specification to the previous Core i5-7600K, which currently costs around £50 more.