Introduction

Intel today debuted its 11th Generation Core "Rocket Lake" desktop processor family. and we have with us the mid-tier Core i5-11600K, which, if combined with the right hardware, could end up being all the CPU you need for maxed out gaming. The new Rocket Lake architecture is Intel's response to a menacingly resurgent AMD and its stunning usurping of the gaming performance crown from Intel last year. The architecture introduces the new "Cypress Cove" CPU core, which Intel claims offers an IPC gain of up to 19% over the previous generation, which should translate into major gaming performance gains.

The sub-$300 desktop processor market has been dominated by 6-core processors since 2018. Intel's first response to the 6-core/12-thread Ryzen 5 series was the Core i5 6-core/6-thread "Coffee Lake" series. As AMD steadily increased IPC with "Zen 2" and the Ryzen 5 3600X, Intel responded with the 6-core/12-thread Core i5-10600K, introducing HyperThreading to this segment. With AMD deciding to hold the 6-core/12-thread configuration for its latest "Zen 3" Ryzen 5 5600X, Intel is sticking with this core count and counting on the increased IPC to clinch the deal in their favor.



The new Cypress Cove CPU core is a back-port of the "Sunny Cove" core from "Ice Lake," to the 14 nm process. Rocket Lake combines up to 8 of these cores with an updated integrated graphics solution based on the Gen12 Xe LP architecture—the same one powering "Tiger Lake" Iris Xe iGPUs. Intel is also introducing its ambitious DLBoost (Deep Learning Boost) feature to the desktop platform with Rocket Lake. DLBoost accelerates AI deep-learning neural net building and training by up to six times compared to native x86 code. Intel sees a future for AI in several client media applications, including image and video manipulation. It's already quite popular on smartphones. The new CPU core also introduces new instruction sets, including AVX-512, or at least a truncated version of it with only those instructions that are relevant to the consumer PC.

With Rocket Lake, Intel is giving its platform I/O a major overhaul, with support for PCI-Express 4.0 x16 discrete graphics, a CPU-attached M.2 NVMe slot with PCIe 4.0 x4, and double the chipset-bus bandwidth compared to the previous generation when paired with a Z590 or H570 chipset motherboard. The company is also introducing a wealth of new overclocking features, which we will detail in the following pages.

The Core i5-11600K is a 6-core/12-thread processor clocked at 3.90 GHz, with a maximum Turbo Boost frequency of 4.90 GHz. The processor features 512 KB of L2 cache per core, and 12 MB of shared L3 cache. Prices of mid-tier 6-core processors are on the boil, with Intel asking $275 for the i5-11600K and its main rival, the Ryzen 5 5600X, priced worse, almost crossing $300. In this review, we take the i5-11600K for a spin to show you if this all you need for maxed out AAA gaming in 2021.

Unboxing and Photography

Our Core i9-11900K and i5-11600K processors came to us in a special package meant for reviewers only. The retail box, pictured above, is made out of paperboard.


The processor is based on the same Socket LGA1200 package as the 10th Gen Comet Lake and should work on not just Intel 500-series chipset motherboards, but also older 400-series ones, with a BIOS update.


The retail Core i5-11600K does not include a cooler, but you're spoiled for choice as any Socket LGA1200 or LGA115x cooling solution should work. Just be sure it can handle a TDP of at least 125 W.

The Rocket Lake Microarchitecture

The new Rocket Lake microarchitecture forms the bedrock of Intel's 11th Gen Core desktop processor family. The architecture aims to introduce some of Intel's latest CPU and iGPU architectures to the desktop platform. It also brings Deep Learning Boost AI acceleration to this form factor, and AVX-512. With Rocket Lake, Intel aims to introduce their first double-digit single-threaded CPU performance gains in five years, and a massive iGPU performance gain over the previous generation.


The Rocket Lake-S die is built on what is hopefully the final refinement of Intel's 14 nm silicon fabrication process. Why Intel didn't go with 10 nm SuperFin is anyone's guess. The company still seems to be transitioning between 14 nm and 10 nm-class nodes and is currently prioritizing mobile and enterprise processors with the new node. The price Intel pays for sticking with 14 nm does not just consist of power/thermal costs rivaling the 10th Gen Comet Lake. CPU cores are also limited to a maximum of eight since the LGA1200 package has limited fiberglass substrate area.

Rocket Lake combines five key design enhancements over the previous generation. These are the new Cypress Cove CPU core, new Gen12 Xe LP integrated graphics, new Gaussian Network Accelerator (GNA) 2.0—a hardware component that enables the Deep Learning Boost (DLBoost) AI acceleration feature—AVX-512, and, lastly, the updated platform I/O that introduces PCI-Express 4.0, along with a chipset bus with double the width over the previous generation.

Cypress Cove

The new Cypress Cove CPU core is a back-port of the "Sunny Cove" core found in Ice Lake processors, to the 14 nm silicon fabrication node. Sunny Cove was originally designed for Intel's 10 nm node. Intel hasn't released core architecture documentation specific to Cypress Cove, but we can extrapolate from what precious little information Intel put out for Sunny Cove.


A CPU core has essentially three components—the front-end, a part that understands the nature of the work and allocates the right hardware resources to get it done; the Execution stage, where the actual number-crunching happens; and the Load/Store stage, which interfaces this work done/to-be-done with the memory system through the processor's cache hierarchy. Intel appears to have directed its engineering efforts toward improving the Execution and Load/Store stages.


There are numerical increases in key components that make up the Execution stage of the core: 25% more allocation width and execution ports, 33% more AGUs, and an additional Store unit in Load/Store. These changes enable support for newer instruction sets—prominently, 512-bit AVX (or AVX-512). Rocket Lake being a client microarchitecture, receives a truncated version of AVX-512 with only those instructions that are relevant to the client segment. The cache sub-system receives a much needed update with the L1 Data cache being enlarged to 48 KB (from 32 KB on Skylake) and the L2 cache being doubled in size to 512 KB. At 16 MB, the L3 cache size hasn't been changed from the previous-generation 8-core parts.

Intel Xe Graphics

The next major component is the Intel Iris Xe integrated graphics solution based on the latest Gen12 Xe LP graphics architecture. This is the same exact technology as in the Tiger Lake iGPUs, but with a slight difference. While the Tiger Lake iGPU gets 96 execution units as shown in the slide above, the Rocket Lake iGPU only has 48. This was probably done to conserve silicon real-estate on the 14 nm die. Intel attempted to make up for the deficit in EUs compared to Tiger Lake by running the iGPU at higher engine clocks and a more generous power budget than the 15-watt Tiger Lake chips launched so far. In any case, Intel claims that the iGPU on Rocket Lake performs up to 50% faster than the Gen9.5 solution found in Comet Lake. Intel updated the media engine of the iGPU to now offer hardware-acceleration of 10-bit AV1 and 12-bit HEVC video formats.

AVX-512

With this generation, Intel is introducing the new AVX-512 instruction set. This evolution of AVX and AVX2 helps accelerate SIMD workloads—similar operations on a lot of data at the same time. The whole AVX-512 instruction set is a vast set of instructions, not all of which are relevant to the client PC use case. Intel has hence truncated the instruction set, with only certain instructions available to client platforms such as Rocket Lake and Ice Lake, while enterprise/HPC products, such as Xeon Scalar processors and Xeon Phi, have different instructions. Since Cypress Cove is derived from Sunny Cove (and not "Willow Cove"), it features Foundational (F), Conflict-Detect (CD), Vector Propulsion Count (VPOPCNTDQ), Vector Length (VL), BFloat16, Vector-AES, etc., but not the Vector Intersect (VP2INTERSECT) instruction Willow Cove supports.

Gaussian Network Accelerator

Next up is GNA 2.0, the hardware component that enables DLBoost, Intel's ambitious new client processor feature that brings AI capabilities to the processor to speed up certain creativity apps that can leverage them. AI-accelerated video and image manipulation has made great strides on smartphones for the past 3+ years, and Intel sees an opportunity for it on the PC, too. DLBoost debuted in 2019 with the 10th Gen Ice Lake mobile processors, and is coming to desktop with Rocket Lake. Intel claims that it accelerates deep-learning neural net building/training by up to six times compared to native x86 machine code, which can help offload the CPU cores.