New Features, Initial Thoughts

Improved Turbo Boost Max Technology 3.0

With the release of the Broadwell-E platform, Intel introduced Turbo Boost Max Technology 3.0 that allowed a single core on those CPUs to run at higher clock speeds than the others, effectively improving single threaded performance. With Skylake-X, Intel has improved the technology to utilize two TWO best cores, rather than just one.

This allows the 8-core and higher count processors from this launch to run at higher frequencies when only one or two cores is being utilized. In the two products that we have clock speeds for, that is a 200 MHz advantage over standard Turbo Boost technology. Intel hopes that this improvement in the technology gives them another advantage in any gaming or lightly threaded workload over the AMD Ryzen and upcoming Threadripper processors.

Cache Hierarchy

Skylake-X processors will also rebalance the cache hierarchy compared to previous generations, rebalancing to more exclusive per-core cache at the expensive of shared LLC. While Broadwell-E had 256KB of private L3 cache per core, and 2.5 MB per core of shared, Skylake-X moves to 1MB of private cache per core and 1.375MB per core of shared.

This shift in cache division will increase the hit rate on the lowest latency memory requests, though we do expect inter-core latency to increase slightly as a result. Intel obviously has made this decision based on workload profiling so I am curious to see how it impacts our testing in the coming weeks.

Overclocking Tweaks

Intel does add three new overclocking capabilities to the Skylake-X processors with this release.

First, we see that Intel has added AVX-512 instruction ratio offsets, allowing you to lower performance of AVX performance to the benefit of power consumption, relieving one bottleneck often cited for extreme overclockers. Second, memory controller trim voltage control was added. And finally, PEG/DMI overclocking is opening up.

The X299 Chipset

Though we stuck with the X99 chipset and socket for Broadwell-E, Skylake-X and Kaby Lake-X will be using a new chipset and a new LGA2066 socket. We have already seen motherboards leaking out and we should have numerous announcements through Computex this week (check back to for all the news!) but now we have preliminary details on what changes it offers.

Fundamentally it looks pretty much the same. The biggest change is one of connectivity – the X299 chipset will now offer up to 24 PCIe 3.0 lanes, mirroring the capability of the Z270 chipset. Compared to the X99 chipset, that only included 8 lanes of PCIe 2.0, this is a significant increase. The DMI connection between the chipset and the processor is also upgrade to DMI 3.0, giving us a doubling of peak throughput (4GB/s rather than 2GB/s). That helps to alleviate the bottleneck from the chipset to the CPU, though a highly saturated system utilizing chipset-based connectivity could still hit speed limitations.

I would expect that concern to be alleviated for a majority of consumers though as the 28 or 44 lanes of PCIe Gen 3.0 provided by the processors (Skylake-X) allows for multi-GPU configurations at x16 or x8 speeds with room for PCIe NVMe storage to boot. Either way, it’s impressive that an X299 system with a 10-core or higher processor would have access to 68 lanes of PCI Express in total – 44 from the CPU and 24 from the chipset.

Default memory speed gets a jump from 2133 MHz on the X99 systems to 2666 MHz on the new X299 systems, giving the new platform another potential advantage. We also have 8x SATA 3 channels, 10x USB 3.0 ports and support for 3-way RAID of PCIe and NVMe drives as a part of this system platform.

Closing Thoughts

Today marks only the announcement of the Skylake-X and Kaby Lake-X platform, but it sets the stage for an interesting summer in the high-end CPU space. AMD threw down the first gauntlet by releasing 8-core processors in the same space that Intel had been limiting to 4-cores. Next, AMD announced its intent to release 16-core processors under the Threadripper brand directly targeting Intel’s profitable halo product line under the X99 platform. Intel’s response is now two-fold – release more and higher core count CPUs, up to 18-cores with 36-threads, while also lowering prices in a couple of key areas. (The $599 8c/16t Core i7-7820X comes to mind.)

It’s still not a perfect setup and Intel is leaving its flank open again for another attack. The $999 price tag for the 10-core Core i9-7900X is aggressive compared to Intel’s own launch last year but I would full expect AMD to offer 16-core Threadrippers for that same price, maybe slightly higher. Intel’s 16-core processor is set to run $1699, giving AMD another chance to offer a matching core/thread count part at a lower price. No, I don’t expect single threaded performance to change at all, and Intel should still have the advantage there (maybe more so with increase clocks) but multi-threaded performance could still swing AMD’s way.

It’s a race to release, and a race that enthusiasts should be excited to see play out. We’ll have more details from Intel and reviews of products first, so stay tuned to PC Perspective for that!

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