AMD Ryzen 5 8640U vs Intel Core i9-11900KF Comparison

The AMD Ryzen 5 8640U and Intel Core i9-11900KF are fundamentally different processors—one a low-power mobile chip, the other a high-power desktop part—yet their average benchmark scores place them within striking distance of each other. The Ryzen 5 8640U averages 26,462 points versus the i9-11900KF’s 26,212, a razor-thin 0.95% margin in favor of the AMD part. Both sit at the 78th percentile among all CPUs, and each lands within 0.4% of its nearest rivals, which include the AMD Ryzen 5 7600 and Intel Core i9-12900HK. The data reveals a stark split: the Intel chip wins 13 of 17 head-to-head tests, often by wide margins, but the AMD chip counters with a few key single-threaded and efficiency-focused victories.

Head-to-Head Benchmarks

The most decisive win for the Intel Core i9-11900KF comes in Cinebench R23 multi-core, where it scores 20,838 against the AMD’s 10,433. That’s a 49.9% advantage—the largest delta in the entire comparison. The Intel part’s 8 cores and 16 threads simply overpower the Ryzen 5 8640U’s 6 cores and 12 threads in heavily threaded workloads. The gap narrows but remains substantial in Cinebench R15 multi-core, where Intel leads 2,100 to 1,663, a 20.8% margin. Geekbench multi-core tells a similar story: Intel scores 10,953, AMD 8,185, a 25.3% deficit for the mobile chip.

Single-threaded performance is closer but still favors Intel in most rendering tests. The i9-11900KF posts 2,941 in Cinebench R23 single-core versus 1,651 for the Ryzen 5 8640U, a 43.9% lead. In Cinebench R15 single-core, Intel wins 296 to 256, a 13.5% edge. The picture flips in Geekbench single-core, where AMD takes a narrow 3.3% win (2,131 vs. 2,062). PassMark’s single-thread test also goes to AMD, but barely: 3,534 vs. 3,527, a 0.2% margin. These near-ties suggest that in lightly threaded, latency-sensitive tasks, the two processors are effectively equals, with AMD holding a slight edge.

The PassMark suite shows Intel dominating across the board. Data compression goes to Intel 325,688 to 230,080, a 29.4% gap. Integer math favors Intel 89,023 to 68,051, a 23.6% win. Floating-point math is similarly lopsided: 52,640 vs. 40,330, a 23.4% margin. Extended instructions (SIMD-heavy workloads) see Intel ahead by 27.3% (22,703 vs. 16,500). Random string sorting is a 24.9% Intel win (37,383 vs. 28,066). Data encryption is closer, with Intel ahead 15,623 to 14,013, a 10.3% edge. PassMark multi-thread shows Intel leading 24,708 to 20,322, a 17.8% advantage.

The Ryzen 5 8640U’s wins are few but noteworthy. Beyond Geekbench single-core and PassMark single-thread, AMD takes PassMark find prime numbers by 4.5% (69 vs. 66) and PassMark physics by a hair (1,033 vs. 1,034, a 0.1% delta). The physics result is effectively a tie. AMD’s four wins are all in tests where the workload is short, single-threaded, or latency-bound, while Intel’s 13 wins span every category of sustained multi-core or data-heavy processing.

Where Each One Wins

The Intel Core i9-11900KF is the clear choice for any workload that scales with cores and threads. Its 49.9% lead in Cinebench R23 multi-core makes it superior for 3D rendering, video encoding, and other content-creation tasks that push all cores simultaneously. The 29.4% win in data compression and 27.3% lead in extended instructions point to advantages in archiving, compression utilities, and scientific computing that uses SIMD instruction sets. Integer and floating-point math wins of roughly 23% indicate strength in general computation, financial modeling, and engineering simulations. The 17.8% multi-thread PassMark lead reinforces that any parallel workload will complete faster on the Intel part.

The AMD Ryzen 5 8640U wins in scenarios where raw throughput matters less than responsiveness. Its 3.3% Geekbench single-core lead and 0.2% PassMark single-thread edge suggest slightly snappier performance in everyday desktop tasks like web browsing, office applications, and light code compilation. The 4.5% win in find prime numbers indicates an advantage in certain integer-heavy, single-threaded algorithms. The physics test, while essentially tied, shows the AMD chip can hold its own in game physics calculations. Critically, the Ryzen 5 8640U achieves these results at a 28W TDP compared to the Intel’s 125W TDP—the data shows the AMD part delivers comparable single-threaded performance with dramatically lower power consumption.

The Verdict

The data supports a clear split decision. For users who prioritize multi-core performance, the Intel Core i9-11900KF is the definitive winner. Its 49.9% lead in Cinebench R23 multi-core and 25.3% edge in Geekbench multi-core are decisive. Any workflow involving rendering, video editing, data processing, or heavy multitasking will see substantially faster completion times on the Intel platform. The i9-11900KF’s 8-core, 16-thread configuration with a 5.30 GHz boost clock simply outmuscles the Ryzen 5 8640U in sustained workloads.

However, the Ryzen 5 8640U is the better choice for mobile or power-constrained environments. Its 28W TDP versus 125W makes it suitable for thin-and-light laptops where battery life and thermals are paramount. The AMD chip’s wins in Geekbench single-core and PassMark single-thread show it can match or slightly exceed the Intel part in everyday responsiveness. The presence of integrated Radeon 760M graphics is another differentiator—the i9-11900KF has no integrated graphics, requiring a discrete GPU. For users who need a capable processor for general productivity, light content creation, and occasional gaming, the Ryzen 5 8640U offers a more balanced package.

The verdict hinges on the use case. Desktop users with a dedicated GPU and a need for maximum multi-core throughput should pick the Intel Core i9-11900KF. Mobile users who value efficiency, single-threaded responsiveness, and integrated graphics should choose the AMD Ryzen 5 8640U. The data does not support one as universally better—they occupy different corners of the performance envelope.

FAQ

Q: Which processor is faster in multi-core workloads?

A: The Intel Core i9-11900KF is significantly faster, winning Cinebench R23 multi-core by 49.9% (20,838 vs. 10,433) and Geekbench multi-core by 25.3% (10,953 vs. 8,185).

Q: Does the AMD Ryzen 5 8640U win any benchmark tests?

A: Yes, it wins 4 of 17 head-to-head tests: Geekbench single-core (by 3.3%), PassMark single-thread (by 0.2%), PassMark find prime numbers (by 4.5%), and PassMark physics (by 0.1%).

Q: How do their average benchmark scores compare?

A: The AMD Ryzen 5 8640U averages 26,462, while the Intel Core i9-11900KF averages 26,212. The AMD chip holds a 0.95% lead in average score, despite losing the majority of individual tests.

Q: What are the core and thread counts?

A: The AMD Ryzen 5 8640U has 6 cores and 12 threads. The Intel Core i9-11900KF has 8 cores and 16 threads.

Q: Do these processors have integrated graphics?

A: Yes, the AMD Ryzen 5 8640U includes Radeon 760M integrated graphics. The Intel Core i9-11900KF has no integrated graphics.

Q: What is the production status of each processor?

A: The AMD Ryzen 5 8640U is listed as Active, while the Intel Core i9-11900KF is End-of-life.

Architecture Differences

The AMD Ryzen 5 8640U and Intel Core i9-11900KF are built on fundamentally different architectures and process nodes. AMD uses the Zen 4 architecture, codenamed Hawk Point, manufactured on TSMC’s 4 nm process. The chip contains 25,000 million transistors on a 178 mm² die. Intel, by contrast, uses the Rocket Lake architecture on Intel’s 14 nm process, with a 276 mm² die size. This process difference is stark: the AMD chip is built on a far more advanced node, which explains how it achieves competitive single-threaded performance at a 28W TDP versus the Intel part’s 125W TDP.

Cache configurations differ notably. The AMD Ryzen 5 8640U has 64 KB of L1 cache per core, 1 MB of L2 cache per core, and 16 MB of shared L3 cache. The Intel Core i9-11900KF has 80 KB of L1 cache per core, 512 KB of L2 cache per core, and also 16 MB of shared L3 cache. The AMD chip’s larger per-core L2 cache (1 MB vs. 512 KB) may contribute to its single-threaded wins, while Intel’s larger L1 cache per core helps in other scenarios.

Memory support is another major divergence. The AMD Ryzen 5 8640U supports DDR5 memory with dual-channel configuration and a memory bandwidth of 89.6 GB/s. The Intel Core i9-11900KF supports DDR4 memory, also dual-channel, with a bandwidth of 51.2 GB/s. AMD’s higher memory bandwidth is a direct result of the newer DDR5 standard, giving it a 75% theoretical bandwidth advantage. Neither processor supports ECC memory.

Both chips use PCIe Gen 4 with 20 lanes (CPU only), but their sockets are incompatible. The AMD Ryzen 5 8640U uses AMD Socket FP8, a mobile socket, while the Intel Core i9-11900KF uses Intel Socket 1200 for desktop. The Intel part has an unlocked multiplier, while the AMD chip is locked. The Intel processor carries a launch MSRP of $513, while the AMD processor has no listed launch MSRP. The AMD chip is part of the 8000 series with a release date in December 2023, while the Intel chip is from the 11th Gen Core series, released in March 2021. The Intel part is now End-of-life, while the AMD part remains in active production.