Intel Core i9-11900K and Core i5-11600K Review: Rocket Lake Blasts Off

Intel's 11th-Gen Rocket Lake processors have finally been cleared for liftoff, with the eight-core $539 Core i9-11900K taking on AMD's potent Ryzen 9 5900X that leads our CPU Benchmark hierarchy, while the six-core $262 Core i5-11600K slots in with more palatable pricing as the mainstream gaming chip to challenge AMD's Ryzen 5 5600X, our current Best CPU for gaming.

The 14nm Rocket Lake family arrives during dark times for Intel in the desktop PC market. AMD's Zen-fueled assault on the desktop has culminated in its powerful Zen 3-powered Ryzen 5000 chips taking the uncontested lead in nearly every metric that matters, including in Intel's long-held gaming stronghold.

Intel says Rocket Lake will retake the gaming crown, but the devastating fallout of the company's failure to transition to 10nm desktop PC chips now ripples through a fifth generation of its processors. As a result, Rocket Lake comes fabbed on the seventh and presumably final iteration of Intel's 14nm process for desktop processors. This after having soldiered on since 2015 as Intel's longest-lived leading-edge node.

However, Rocket Lake comes with a powerful new addition — Cypress Cove, Intel's first new architecture for desktop PC chips in six years, which Intel says grants a 19% increase in IPC. But Cypress Cove comes with a big tradeoff: Rocket Lake tops out at eight cores and sixteen threads, a step back from the previous-gen 10-core Comet Lake i9 models that pales in comparison to AMD's beastly 16-core Ryzen 9 5950X flagship. 

The lowered core count is an unavoidable side effect of Intel basing its new architecture on a design that originally debuted with its 10nm Ice Lake processors, but the decision to etch it onto the 14nm process left its chip designers with a leaner transistor density budget that ultimately resulted in fewer cores.

Intel says this tactic, which is called backporting, was necessary because 10nm couldn't support the higher frequencies needed for desktop PCs. Intel claims the increased IPC and faster frequencies should offset the reduced core count in most work. However, as you'll see in our testing, the reduced core count can lead to lower gen-on-gen performance in some heavily-threaded applications. That certainly hasn't stopped Intel from charging a premium for its new 11900K flagship, though, which comes with a $51 upcharge over the prior-gen model.

Rocket Lake has plenty of notable advances, though: Intel stepped forward to faster DRAM speeds (though that comes with a big caveat), finally adopted the PCIe 4.0 interface, added AVX-512 support and AI-boosting DL Boost technology, and also moved to the integrated UHD Graphics 750 engine that hails from the company's 10nm Tiger Lake chips. Rocket Lake also has other gaming optimizations with added support for Resizable Bar, which boosts gaming performance with supported discrete GPUs. The chips also cater to the enthusiast crowd with a host of overclocking features to wring more performance from the silicon, including unlocked memory overclocking with cheaper B- and H-series motherboards.

However, while much of AMD's successful formula has consisted of more cores, a newer architecture, and a denser 7nm node, Intel has launched its new flagship on an older, less-efficient 14nm node with fewer cores. As a result, Intel has attempted to offset the reduced core count by dialing power consumption to the extreme to maximize performance. The Core i9-11900K is impressive in gaming and lightly-threaded work, but it trails the similarly-priced Ryzen 9 5900X by large margins in threaded applications and doesn't cement itself well enough as a gaming leader to justify its premium price tag. 

Meanwhile, the six-core twelve thread Core i5-11600K lands with a much friendlier $262 price point that's much more competitive with AMD's comparable chips. In light of its price point, it has a very competitive price-to-performance ratio with the $300 Ryzen 5 5600X in a broad swath of games and applications. While the Core i5-11600K might not claim absolute supremacy, its mixture of price and performance makes it a solid buy. Provided, of course, that you can find any of these chips at close to sane pricing. 

Intel Rocket Lake Core i9-11900K and Core i5-11600K Specifications and Pricing 

Intel spreads the Rocket Lake (RKL-S) chips across the familiar Core i9, i7, and i5 families, but Comet Lake Refresh (CML-R) chips step in for Core i3 and Pentium. Those chips feature the same architecture as other Comet Lake chips but come with slightly increased clock speeds. You can find more detail on those models here.

Intel's chip frequencies have become a confusing array of four different flavors of Turbo Boost, many with both single- and multi-core ratios, that differ based on each family of chips. We've narrowed these listings down to the peak boost frequencies in the table below, with each indicating the peak boosting tech used. We've also narrowed down the list of chips to the most important models. We'll circle back with a complete list of chips, specs, and boost definitions on the following page.

As we've seen for several chip generations, Intel also offers graphics-less F-series models that have the same specs as their full-featured counterparts but come at a lower price point. Keep those in mind if you don't need integrated graphics.

The eight-core Core i9-11900K slots in as the flagship model for the Rocket Lake family. Fast clock speeds are a clear attraction, but they come at the expense of power — two of the chip's cores boost to a peak of 5.3 GHz, and all cores can operate at 4.8 GHz simultaneously. The 11900K has a 125W PL1 power rating (at the base frequency) and a 250W PL2 (boost) rating, both of which are identical to the previous-gen 10900K despite having two fewer cores. 

The Core i9 K and KF models are Intel's first chips to come with Adaptive Boost Technology (ABT), which allows the processors to dynamically boost to higher all-core frequencies based upon available thermal headroom and electrical conditions (a bit more detail below). This new tech will feel decidedly familiar to AMD fans, as it operates in a very similar fashion to AMD's existing boost mechanism that's present in newer Ryzen processors. 

The eight-core 16-thread flagship Core i9-11900K comes with a suggested $539 price tag, a $51 markup over the previous-gen ten-core 10900K. The 11900K slots in for $10 less than the Ryzen 9 5900X, which means we're looking at an eight-core chip taking on a 12-core 24-thread chip that will easily beat it in threaded workloads. Intel's obvious goal here is to beat the 5900X at gaming so it can justify the price tag.

Notably, Intel's non-K Core i9 and i7 models carry the same pricing as their prior-gen counterparts. As per usual, K SKUs come without coolers, and you'll need a capable cooler to unlock the best of Rocket Lake.

The $399 Core i7-11700K slots into the massive pricing gap between the $299 Ryzen 5 5600X and $449 Ryzen 7 5800X. Core counts are no longer the distinction between the Core i9 and Core i7 families — both families come with eight cores and 16 threads. Instead, a few frequency bins separate the chips, courtesy of Intel's ABT and Thermal Velocity Boost tech, and the differences in memory Gear modes that we'll explain below. As such, the 11700K tops out 5 GHz on two cores via Turbo Boost 3 tech, and all cores can stretch up to 4.6 GHz simultaneously. At $399, Intel commands a $25 premium over the previous-gen 10700K.

The Core i5-11600K contends directly with the $299 Ryzen 5 5600X in the heart of the mainstream gaming market, so this is an exceptionally important model. The $262 six-core Core i5-11600K matches the pricing of the previous-gen i5-10600K. The 11600K boosts to a peak of 4.9 GHz on two cores and can maintain a 4.6 GHz all-core frequency. 

The 11600K comes with a 125W PL1 rating, the same as the previous-gen 10600K, but has a 251W PL2, a whopping 69W increase compared to the previous 182W limit.

The Core i5-11400 also stands out as a potentially great deal, with $182 (or $157 for the F-series part) being a solid price for a six-core 12-thread processor. We have this processor inbound for review.

Intel has stepped forward from DDR4-2933 to DDR4-3200, but the company also introduced a new paradigm with Rocket Lake: Only the Core i9 chips support DDR4-3200 in an optimal configuration at stock settings. This setting is called 'Gear 1,' and signifies that the memory controller and memory operate at the same frequency (1:1), thus providing the lowest latency and best performance in lightly-threaded work, like gaming.  

All other Rocket Lake chips only officially support DDR4-3200 with the 'Gear 2' setting, which allows the memory to operate at twice the frequency of the memory controller (2:1) and results in higher data transfer rates, which can benefit some threaded workloads but also results in higher latency that can lead to reduced performance in some applications.

Intel justifies the new segmentation approach because memory controllers fall into the binning equation, meaning chips with slower controllers are only rated for DDR4-3200 in Gear 2 mode. The official top speed for the Gear 1 setting is DDR4-2933 for all Core i7 and i5 chips, and running DDR4-3200 in lower-latency Gear 1 mode is considered overclocking. Intel isn't known for harsh memory overclocking restrictions when processing returns, but running memory beyond the spec does technically void your warranty.

Intel's Rocket Lake Die Shots and Comparisons 

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We aren't prepared to sacrifice our sample by doing a risky delid, but a daring enthusiast recently delidded a Core i7-11700K processor and shared the results. We used the resulting photos to calculate Rocket Lake's die's size through a photo lineup compiled from Der8auer's die analysis article (via @harukaze5719).

Intel has confirmed that all Rocket Lake-S chips come with the same eight-core die, with two cores disabled for the six-core models. Surprisingly, based on our rough projections, Rocket Lake's eight-core die is about 34% larger than the ten-core Comet Lake die.

In an odd twist, this could be a good development for enthusiasts because it should help make the chips easier to cool compared to the previous-gen models — the 11900K has the same peak power specifications and 34% more silicon area from which to dissipate the thermal load. That should bode well for the six core models, too, which have more inactive silicon to help absorb heat from neighboring cores. However, Intel has obviously decided to consume the extra thermal headroom by increasing the 11600K's power limit under heavy load by 69 watts. 

Intel chalks much of the die size disparity up to GPU and CPU cores that are physically larger than those found on Comet Lake, a byproduct of backporting from 10nm to 14nm, along with the increased number of graphics EUs.

Intel could have shrunk or removed the integrated graphics engine to cram in more CPU cores within its power, performance, area, and cost (PPAC) targets, but integrated graphics are a key requirement for the high-volume OEM systems market that tends to leverage on-chip graphics rather than discrete GPUs. As a result, Intel says it chose this balance of units to meet its design goals across the broader desktop PC market.

Intel's 14nm process is ultra-mature, so we assume yields are superb, and also that the majority of its chipmaking equipment is depreciated, meaning it should be relatively cost-effective to punch out a flood of Rocket Lake chips while AMD remains supply constrained. However, fabbing a larger die exposes the chips to a greater chance of defects, thus complicating the binning process, potentially reducing yield, and resulting in fewer die per wafer. All of these factors conspire to increase manufacturing costs, which could help explain Intel's higher pricing for its highest-binned SKUs.

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