AMD Ryzen 5 8540U vs AMD Ryzen 5 8640U Comparison

The AMD Ryzen 5 8640U and AMD Ryzen 5 8540U are two closely related 6-core, 12-thread mobile processors from AMD’s 8000 series, both built on the Zen 4 architecture under the Hawk Point codename. Both share the same 28W TDP, the same 4.90 GHz boost clock, and the same 16 MB of shared L3 cache, yet benchmark data reveals a consistent performance split between the two. The 8640U takes the overall win in 12 out of 15 head-to-head comparisons, while the 8540U counters with victories in single-core workloads. This analysis breaks down the measurable differences, architectural nuances, and which processor suits which scenario based strictly on the provided data.

Head-to-Head Benchmarks

The Ryzen 5 8640U dominates multi-threaded and compute-heavy workloads, often by double-digit margins. In PassMark’s integer math test, the 8640U scores 68,051 against the 8540U’s 57,755, a decisive 17.8% advantage. Floating-point math tells a similar story: 40,330 versus 34,958, a 15.4% lead. Data encryption shows a 14.4% gap (14,013 vs. 12,245), and random string sorting lands at 15.1% in favor of the 8640U (28,066 vs. 24,375). The 8640U also leads in PassMark’s multithread score by 10.9% (20,322 vs. 18,332) and in data compression by 10.3% (230,080 vs. 208,619).

Cinebench results reinforce this pattern. In Cinebench R23 multi-core, the 8640U posts 10,433 points versus 9,721.5 for the 8540U, a 7.3% advantage. The older Cinebench R15 multi-core test shows a similar 6.8% lead (1,663 vs. 1,557.5). Even extended instruction workloads (PassMark) favor the 8640U by 10.7% (16,500 vs. 14,900). The smallest multi-core win comes in PassMark physics, where the 8640U edges ahead by just 0.5% (1,033 vs. 1,028), and the two are perfectly tied at 69 in PassMark’s find prime numbers test.

The 8540U, however, takes the single-core crown. In Cinebench R23 single-core, it scores 1,714.5 against 1,651 for the 8640U, a 3.7% lead. PassMark single-thread results also favor the 8540U by 2.9% (3,639 vs. 3,534). In Cinebench R15 single-core, the gap narrows to just 1.2% (256 vs. 253), still favoring the 8640U. Notably, the 8540U’s single-core wins are not enough to offset the 8640U’s broader multi-threaded dominance, which shows in the overall win count: 12 for the 8640U, 3 for the 8540U.

Looking at the broader context, the 8640U’s average benchmark score of 26,462 places it on par with the Intel Core i9-12900HK (26,469, 0% delta) and the Intel Core i7-1280P (26,469, 0% delta). The 8540U’s average of 26,187 is similarly competitive, sitting slightly below the Intel Core i9-11900KF (26,212, -0.1% delta) and above the AMD Ryzen 5 8640HS (26,106, +0.3% delta). Both CPUs land in the 78th percentile of all CPUs, indicating they are statistically equivalent in overall performance tier, despite the 8640U’s edge in raw throughput.

Architecture Differences

Both processors are built on TSMC’s 4nm process and use the Zen 4 architecture, but the silicon itself differs. The 8640U packs 25,000 million transistors on a 178 mm² die, while the 8540U has 20,900 million transistors on a smaller 137 mm² die. This 4,100 million transistor difference and 41 mm² die-size gap explain why the 8640U consistently outperforms in multi-threaded tasks—it has more hardware resources to draw upon, even though both chips expose 6 cores and 12 threads.

The cache hierarchy is identical on paper: 64 KB of L1 per core, 1 MB of L2 per core, and 16 MB of shared L3. The base clocks differ, though. The 8640U starts at 3.50 GHz, while the 8540U begins at 3.20 GHz—a 300 MHz gap that contributes to the 8640U’s multi-core lead. Both boost to 4.90 GHz, which is why the 8540U can still win single-core tests; its lower base clock may allow for different power/thermal behavior under light loads.

The integrated graphics also differ. The 8640U carries a Radeon 760M, while the 8540U has a Radeon 740M. This is a meaningful distinction for users who rely on iGPU performance, though the benchmark data provided does not include iGPU scores. Both chips support DDR5 memory in dual-channel configuration with 89.6 GB/s bandwidth, and neither supports ECC memory.

The PCIe lane count is another differentiator. The 8640U provides Gen 4 with 20 lanes (CPU only), while the 8540U offers Gen 4 with 14 lanes (CPU only). This affects expansion capability for NVMe drives and dedicated GPUs in mobile designs. The socket also differs: the 8640U uses AMD Socket FP8, while the 8540U uses AMD Socket FP7. The 8640U has a more complex part number list (three variants), while the 8540U has two.

Both chips share the same release date (2023-12-05), production status (Active), and unlocked multiplier status (false). Neither has a listed launch MSRP. The 8640U’s transistor count and die size are the primary physical differentiators, while the socket and PCIe lane counts are the practical compatibility differences.

FAQ

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

A: The Ryzen 5 8640U wins all multi-core benchmarks. It leads by 7.3% in Cinebench R23 multi-core (10,433 vs. 9,721.5) and by 17.8% in PassMark integer math (68,051 vs. 57,755). Its average benchmark score is 26,462 versus 26,187 for the 8540U.

Q: Does the Ryzen 5 8540U have any advantages?

A: Yes, in single-core performance. It wins Cinebench R23 single-core by 3.7% (1,714.5 vs. 1,651) and PassMark single-thread by 2.9% (3,639 vs. 3,534). It also has a smaller die (137 mm² vs. 178 mm²) and fewer transistors (20,900 million vs. 25,000 million), which could imply lower manufacturing costs.

Q: Are these CPUs compatible with the same motherboards?

A: No. The 8640U uses AMD Socket FP8, while the 8540U uses AMD Socket FP7. They also differ in PCIe lanes: the 8640U has 20 Gen 4 lanes, while the 8540U has 14 Gen 4 lanes (CPU only).

Q: How do these CPUs compare to Intel rivals?

A: The 8640U’s average score of 26,462 matches the Intel Core i9-12900HK (26,469, 0% delta) and Intel Core i7-1280P (26,469, 0% delta). The 8540U’s average of 26,187 is 0.1% below the Intel Core i9-11900KF (26,212) and 0.3% above the AMD Ryzen 5 8640HS (26,106).

Q: Is there a difference in integrated graphics?

A: Yes. The 8640U includes a Radeon 760M, while the 8540U has a Radeon 740M. The data does not include iGPU benchmark scores, so the performance gap cannot be quantified here.

Q: Which one has a higher base clock?

A: The 8640U has a 3.50 GHz base clock, while the 8540U has a 3.20 GHz base clock. Both boost to 4.90 GHz, and both are 28W TDP parts.

Specification Differences

| Specification | AMD Ryzen 5 8640U | AMD Ryzen 5 8540U |

|---|---|---|

| Base Clock | 3.50 GHz | 3.20 GHz |

| Socket | AMD Socket FP8 | AMD Socket FP7 |

| Transistors | 25,000 million | 20,900 million |

| Die Size | 178 mm² | 137 mm² |

| PCIe | Gen 4, 20 Lanes (CPU only) | Gen 4, 14 Lanes (CPU only) |

| Integrated Graphics | Radeon 760M | Radeon 740M |

| Part Number | 100-000001324(FP7r2)100-000001376(FP7)100-000001313(FP8) | 100-000001326(FP7r2)100-000001333(FP7) |

| Cinebench R23 Single-Core | 1,651 | 1,714.5 |

| Cinebench R23 Multi-Core | 10,433 | 9,721.5 |

| PassMark Single-Thread | 3,534 | 3,639 |

| PassMark Integer Math | 68,051 | 57,755 |

| PassMark Floating-Point Math | 40,330 | 34,958 |

| PassMark Multithread | 20,322 | 18,332 |

| Average Benchmark Score | 26,462 | 26,187 |

The Verdict

The Ryzen 5 8640U is the clear choice for multi-threaded productivity. Its 17.8% lead in integer math, 15.4% lead in floating-point math, and 7.3% lead in Cinebench R23 multi-core make it the stronger all-around processor for rendering, compilation, and data-heavy tasks. It also offers more PCIe lanes (20 vs. 14) and a higher base clock (3.50 GHz vs. 3.20 GHz), which are meaningful for system builders. The 8640U’s transistor count of 25,000 million versus 20,900 million suggests it is the more capable silicon, and its average benchmark score of 26,462 edges out the 8540U’s 26,187.

The Ryzen 5 8540U is not without merit. Its single-core wins in Cinebench R23 (1,714.5 vs. 1,651) and PassMark single-thread (3,639 vs. 3,534) make it slightly better for lightly threaded applications like older games or single-threaded scripts. Its smaller die (137 mm² vs. 178 mm²) and lower transistor count could translate to efficiency benefits, though no power data is provided to confirm this. The 8540U is also a viable option if socket FP7 compatibility is a requirement, as it will not fit in FP8 sockets.

For most users, the 8640U is the better buy based on the data. It wins 12 of 15 benchmarks, including every multi-core test, and matches the 8540U in overall percentile ranking (78th). The 8540U only makes sense if single-core performance is the sole priority or if the system design mandates the FP7 socket. Both CPUs are active production parts with identical release dates, but the 8640U’s broader performance envelope and higher resource count make it the default recommendation for anyone who values throughput over the 8540U’s narrow single-core edge.