AMD Ryzen 7 8840U vs AMD Ryzen 9 5900HX Comparison

The AMD Ryzen 7 8840U and AMD Ryzen 9 5900HX are both 8-core, 16-thread mobile processors, but the recorded data shows they serve distinctly different purposes. The 8840U wins 15 of the 23 head-to-head benchmark comparisons, while the 5900HX takes 8. The 8840U leads decisively in single-threaded and lightly threaded workloads, while the 5900HX counters with higher multi-threaded scores in several specific tests. The 8840U also posts a higher average benchmark score in its own database entry at 23982, though the 5900HX counters with an average of 24822, reflecting the different test sets in each processor’s profile. The overall percentiles are nearly identical, with the 8840U at the 76th percentile and the 5900HX at the 77th percentile of all CPUs.

Where Each One Wins

The Ryzen 7 8840U is the clear winner in single-core performance. It beats the 5900HX by 11.1% in 3dMark single-thread (979 vs 881), by 14.4% in Cinebench R23 single-core (1703 vs 1488), and by 9.9% in Geekbench single-core (1970 vs 1792). This advantage carries over to 2-thread workloads, where the 8840U posts 1863 versus 1720, an 8.3% lead. In Cinebench R15 single-core, the margin is 10.8% (266 vs 240). The 8840U also excels in integer-heavy tasks like prime number finding, scoring 78 versus 53, a massive 47.2% advantage, and in physics simulations, where it scores 1176 versus 909, a 29.4% lead. The 8840U also wins in floating-point math (48820 vs 47556, up 2.7%) and random string sorting (32158 vs 30042, up 7%).

The Ryzen 9 5900HX takes the crown in sustained multi-threaded workloads. It wins 3dMark 16-thread by 12.3% (6490 vs 5691), 3dMark 8-thread by 9.4% (5406 vs 4896), and 3dMark max-thread by 12.5% (6487 vs 5677). In Cinebench R15 multicore, the 5900HX leads by 3.9% (2106 vs 2024). The 5900HX also dominates in data compression (287793 vs 267525, up 7%), data encryption (18188 vs 16072, up 11.6%), extended instructions (19488 vs 18654, up 4.3%), and integer math (86735 vs 85740, up 1.1%). These wins point to workloads that scale with sustained power delivery and raw throughput.

The split is clean: the 8840U wins where responsiveness and single-thread efficiency matter, while the 5900HX wins where all cores are hammered simultaneously for extended periods.

Architecture Differences

The two processors come from different generations and manufacturing processes. The Ryzen 7 8840U uses the Zen 4 architecture, codenamed Hawk Point, built on a 4 nm process at TSMC. The Ryzen 9 5900HX uses Zen 3, codenamed Cezanne, on a 7 nm process, also at TSMC. Transistor counts differ substantially: the 8840U packs 25,000 million transistors on a 178 mm² die, while the 5900HX has 10,700 million transistors on a 180 mm² die.

Both have 8 cores and 16 threads, with identical base clocks of 3.30 GHz. The boost clocks differ: the 8840U boosts to 5.10 GHz, while the 5900HX tops out at 4.60 GHz. This clock advantage explains the 8840U’s single-thread dominance. The thermal design power also diverges: the 8840U is rated at 28 W, while the 5900HX is rated at 45 W. The higher TDP of the 5900HX supports its multi-threaded wins but comes at the cost of efficiency.

Cache configurations are similar in L1 and L3, with both offering 64 KB L1 per core and 16 MB shared L3. The L2 cache differs: the 8840U has 1 MB per core, while the 5900HX has 512 KB per core. The 8840U also uses a different socket (AMD Socket FP8) compared to the 5900HX (AMD Socket FP6). Memory support diverges as well: the 8840U uses DDR5 with a dual-channel bus and 89.6 GB/s bandwidth, while the 5900HX uses DDR4 with 68.3 GB/s bandwidth. PCIe generations also differ, with the 8840U supporting Gen 4 with 20 lanes (CPU only) versus the 5900HX’s Gen 3.

Integrated graphics differentiate them further: the 8840U pairs with Radeon 780M, while the 5900HX uses Radeon Vega 8. The 8840U’s multiplier is locked, while the 5900HX is unlocked, allowing overclocking on the older part. Release dates show the 8840U launched in December 2023, roughly two years after the 5900HX’s January 2021 debut.

FAQ

Q: Which processor has the higher boost clock?

A: The AMD Ryzen 7 8840U boosts to 5.10 GHz, which is 0.50 GHz higher than the Ryzen 9 5900HX’s 4.60 GHz.

Q: How do they compare in single-threaded performance?

A: The 8840U wins every single-thread test in the head-to-head comparison, with margins ranging from 9.9% in Geekbench single-core to 14.4% in Cinebench R23 single-core.

Q: Which processor is better for multi-threaded workloads?

A: The 5900HX wins the 3dMark multi-threaded tests (16-thread, 8-thread, max-thread) and Cinebench R15 multicore, but the 8840U wins Cinebench R23 multicore by 1% and Geekbench multicore by 10.2%.

Q: What memory types do these processors support?

A: The 8840U supports DDR5 memory with 89.6 GB/s bandwidth, while the 5900HX supports DDR4 memory with 68.3 GB/s bandwidth.

Q: Are both processors unlocked for overclocking?

A: No, the 8840U has a locked multiplier, while the 5900HX is unlocked.

Q: How do their transistor counts compare?

A: The 8840U has 25,000 million transistors on a 178 mm² die, while the 5900HX has 10,700 million transistors on a 180 mm² die.

Specification Differences

The two processors differ in several key specification fields, all sourced from the database:

| Field | AMD Ryzen 7 8840U | AMD Ryzen 9 5900HX |

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

| Boost clock | 5.10 GHz | 4.60 GHz |

| TDP | 28 W | 45 W |

| Socket | AMD Socket FP8 | AMD Socket FP6 |

| Architecture | Zen 4 | Zen 3 |

| Codename | Hawk Point | Cezanne |

| Process node | 4 nm | 7 nm |

| Transistors | 25,000 million | 10,700 million |

| Die size | 178 mm² | 180 mm² |

| L2 cache | 1 MB (per core) | 512 KB (per core) |

| Memory support | DDR5 | DDR4 |

| Memory bandwidth | 89.6 GB/s | 68.3 GB/s |

| PCIe | Gen 4, 20 Lanes (CPU only) | Gen 3 |

| Integrated graphics | Radeon 780M | Radeon Vega 8 |

| Multiplier unlocked | false | true |

| Release date | 2023-12-05 | 2021-01-11 |

| Part number | 100-000001323 (FP7r2), 100-000001375 (FP7), 100-000001312 (FP8) | 100-000000300 |

The L1 and L3 caches are identical (64 KB per core and 16 MB shared, respectively), and both have 8 cores, 16 threads, and a base clock of 3.30 GHz. Neither supports ECC memory.

Head-to-Head Benchmarks

The largest win for the 8840U comes in passmark find prime numbers, where it scores 78 versus 53, a 47.2% advantage. This is followed by passmark physics, where the 8840U leads 1176 to 909, a 29.4% margin. In Cinebench R23 single-core, the 8840U wins by 14.4% (1703 vs 1488), and in 3dMark single-thread, it leads by 11.1% (979 vs 881). The 8840U also wins passmark single-thread by 11.5% (3543 vs 3178), Cinebench R15 single-core by 10.8% (266 vs 240), Geekbench multicore by 10.2% (9610 vs 8720), and Geekbench single-core by 9.9% (1970 vs 1792). Smaller wins for the 8840U include 3dMark 2-thread (8.3%), passmark random string sorting (7%), passmark multithread (4.6%), passmark floating-point math (2.7%), Cinebench R23 multicore (1%), and 3dMark 4-thread (0.1%).

The 5900HX’s biggest win is in 3dMark max-thread, where it scores 6487 versus 5677, a 12.5% margin. It also wins 3dMark 16-thread by 12.3% (6490 vs 5691), passmark data encryption by 11.6% (18188 vs 16072), and 3dMark 8-thread by 9.4% (5406 vs 4896). Passmark data compression goes to the 5900HX by 7% (287793 vs 267525), passmark extended instructions by 4.3% (19488 vs 18654), and Cinebench R15 multicore by 3.9% (2106 vs 2024). The 5900HX also wins passmark integer math by a narrow 1.1% (86735 vs 85740).

The pattern is consistent: the 8840U wins every single-thread and lightly threaded test, plus several math and physics workloads, while the 5900HX wins the heavy multi-threaded 3dMark tests and data-intensive passmark workloads.

The Verdict

The data points to the AMD Ryzen 7 8840U for users who prioritize single-thread responsiveness, light multitasking, and efficiency. Its 28 W TDP, 5.10 GHz boost clock, and DDR5 memory support make it well-suited for thin-and-light laptops where battery life and snappy application performance matter. The 8840U’s wins in Geekbench multicore (10.2% ahead) and Cinebench R23 multicore (1% ahead) show that even in some multi-threaded scenarios, the newer architecture can hold its own despite the lower power envelope.

The AMD Ryzen 9 5900HX is the pick for sustained, heavily threaded workloads that can exploit its 45 W TDP. Its wins in 3dMark 16-thread, 8-thread, and max-thread tests, along with data compression and encryption, indicate it handles long-running all-core loads better. The unlocked multiplier and higher power ceiling make it attractive for users who want to squeeze out extra performance in a larger chassis with better cooling.

The average benchmark scores in each processor’s own database profile favor the 5900HX (24822 vs 23982), but the head-to-head results tell a more nuanced story. The 8840U wins 15 of 23 comparisons, and its margins in single-thread tests are decisive. The 5900HX wins 8 comparisons, with its largest margins concentrated in the 3dMark multi-threaded suite. For most everyday tasks, the 8840U’s superior single-core performance will be more noticeable. For rendering, video encoding, or other all-core workloads, the 5900HX’s sustained throughput gives it the edge. The percentile rankings are essentially tied (76th vs 77th), confirming that both are capable processors, but they excel in different domains. Choose the 8840U for modern efficiency and single-thread speed, or the 5900HX for raw multi-threaded endurance.