Skylake-X review: Intel Core i9-7900X and the X299 platform

Introduction Intel's new X-Series consists of i5, i7, and reissued i9 processors, all of which require the same X299 chipset that comes with the LGA2066 socket. The S-series processors will continue to be used with the 200 chipset. In some applications and games, we've encountered performance trends that didn't match our expectations. Considering that Skylake X has a speed advantage due to higher clock speeds as well as new architectural... Intel has reduced the shared Last Level Cache (LLC-L3) and transferred it from an inclusive to a non-inclusive (but exclusive) approach. This was done with the help of an efficient caching algorithm that improves the hit rate of the L2 cache ... The Basin Falls X299 chipset The Kaby Lake-X and Skylake-X processors sit in an LGA2066 socket (R4), powered by an X299 chipset with 6 watts of power, underscoring Intel's strategy of using server chipsets for their HEDT- Li... Why should it always only hit AMD when a change of architecture leads to application-specific "collapses" in the expected performance or, more simply put, the CPU in certain applications simply does not... Ashes of the Singularity: Escalation Because we were just so nice, we continue the high-altitude flight of the overclocked Core i7-6950X, because even with this benchmark the optimization problem described above is very clear:... Grand Theft Auto V (DX11) GTA V restores the old pecking order and also shows two things. First, it's still an Intel domain, but AMD has made up for it with the Ryzen CPUs! It's really amazing how to deal with some fine... Project Cars (DX11) Even with Project Cars, the chemistry between the new CPU and the engine is right, even though it was observed time and again that all 10 cores clocked up to 4.0 GHz, even though they were not all busy. But we would... Introduction During the launch article of AMD's Ryzen 7 CPUs, we had already explained all workstation and HPC benchmarks in great detail and also questioned the background for many results in some cases even down to the last detail. En... Important preliminary remark Since Intel no longer realizes the contact between Die and Heatspreader by metallic solder at Skylake-X and Kaby Lake-X, but also uses cheaper TIM (Thermal Interface Material) to use the same way. Cooling with the Chiller crowbar In order to be able to achieve usable (overclocking) results, we had to switch from the normal water cooling to the Alphacool Ice Age Chiller 2000, as already mentioned in the previous chapter. ... What is left for us after all these pages as a summary? Intel's market leadership in recent years is ultimately based on a continuous offer of more or less large updates, which of course also this time a certain amount of expected...

Intel has reduced the shared Last Level Cache (LLC-L3) and transferred it from an inclusive to a non-inclusive (but exclusive) approach. This was done with the help of an efficient caching algorithm that maximizes the hit rate of the L2 cache. This reduces the L3 cache per core to 1.375 MB, making it a kind of residual cache that captures the data that is thrown out of the private L2 cache.

Intel has also increased the per-core Mid Level Cache (MLC-L2) from 256 KB to 1 MB, benefiting from multi-threaded performance. Unfortunately, Intel has not provided any information on how these changes to its Skylake core design were technically implemented in The.

Cache & Memory Latency and Bandwidth

IPC, AVX, Encryptions

Due to the limited time until the Skylake X launch, we used a preliminary set of benchmarks to compare IPC performance. We've also worked with various BIOS updates, so it's quite possible that future optimizations or a more complex set of workloads can reveal completely different averages than current ones. For all subsequent tests we have chosen a static clock frequency of 3.0 GHz. It is also important to note that Intel does not explicitly provide us with the source of improvements to the IPCs of 15 and 15. 10 percent for single-threaded or multi-threaded workloads. Instead, Intel relies on the Spec*int_rate_base2006 benchmark, which has a fairly high error rate of +/- 5 percent.

The single-threaded Cinebench test run shows no big differences in performance average between the Skylake-X Core i9-7900K, the Kaby Lake i7-7700K and the Skylake Core i7-6700K. Slight improvements of 5.69 percent compared to the Broadwell-E i7-6950X. With the switch to the multi-thread test run of the Cinebench, the differences between the ten-core processors and the rest become greater and the focus is now on the i7-7900X and the i7-6950X, where we were able to determine a delta of 1.93 percent.

The Core i9-7900X has two 256-bit-wide AVX FMA units per core that work in parallel, while AMD splits 256-bit AVX operations into two FMA units per core. Intel disables one FMA unit per core on the Skylake X models with fewer than ten cores. Thus, the i9-7900X has a system-immanent advantage in the y-cruncher benchmark, which is both a single and a multi-threaded program that calculates the number Pi with AVX instructions. In fairness, we used version 0.7.2.9469, which already comes with a Ryzen optimization.

The test results of the i9-7900X, when only one core is used, are nearly twice as high as those of the previous model, which is probably mainly due to Intel's AVX2 optimization. The advantage is equally evident in the multi-thread test. Intel provides AVX-512 support for Skylake processors, but does not implement all of the 11 features into the desktop chips. Instead, selected opportunities are offered in specific market segments.

The Zen architecture relies on two AES modules to accelerate encryption, so it's little wonder that the Ryzen chips dominate the AES-256-ECB single-core test run. Intel processors, on the other hand, play their advantage of the larger number of CPU cores in threaded AES workloads.

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