AMD Ryzen 7 8840HS vs AMD Ryzen 9 3900XT Comparison

The AMD Ryzen 9 3900XT and AMD Ryzen 7 8840HS are both 84th percentile CPUs, but they achieve that standing through opposite strategies. The 3900XT is a desktop part built for raw throughput, winning 14 of 17 head-to-head benchmarks, while the 8840HS is a mobile chip that wins on single-thread efficiency. The data shows the 3900XT is the overwhelming choice for multi-threaded workloads, with a 111.6% lead in Cinebench R23 multi-core and a 170.9% lead in PassMark find prime numbers. The 8840HS, however, counters with a 24.4% advantage in PassMark single-thread and a 13.6% edge in Geekbench single-core, making it the better pick for lightly-threaded tasks where power draw matters. The 3900XT’s 12 cores and 24 threads simply overpower the 8840HS’s 8 cores and 16 threads in almost every sustained workload. The 8840HS is not a performance failure—it is a different tool, one optimized for a 28W TDP and integrated graphics, whereas the 3900XT is a 105W desktop beast.

The Verdict

Pick the AMD Ryzen 9 3900XT if you need maximum multi-threaded performance on a desktop. The data is unambiguous: it leads the 8840HS by 111.6% in Cinebench R23 multi-core (27688 vs 13082) and by 62.2% in PassMark data encryption (28634 vs 17650). Its 12 cores and 24 threads give it a 30.4% advantage in PassMark multithread (32575 vs 24990), making it the superior choice for rendering, compilation, or any workload that scales with core count. The 3900XT also has a 54.4% lead in data compression (452328 vs 292888), which directly benefits archiving and file management tasks. It is the clear winner for anyone building a high-throughput workstation.

Pick the AMD Ryzen 7 8840HS if you prioritize single-thread speed and mobile integration. It wins PassMark single-thread by 24.4% (3626 vs 2742) and Geekbench single-core by 13.6% (1899 vs 1640). Its 5.10 GHz boost clock outpaces the 3900XT’s 4.70 GHz, and its 4nm process node delivers that performance at a 28W TDP versus the 3900XT’s 105W. It also includes Radeon 780M integrated graphics, something the 3900XT lacks entirely. This chip belongs in a thin-and-light laptop where battery life and everyday responsiveness are more important than raw core counts.

The verdict is straightforward: the 3900XT is for compute-heavy desktop rigs, the 8840HS is for efficient mobile systems. The average benchmark scores are nearly identical (33736 vs 33667, a 0.2% difference), but that parity hides the fact that the 3900XT wins on brute force while the 8840HS wins on speed per thread.

FAQ

Q: Which CPU has the higher single-core performance?

A: The AMD Ryzen 7 8840HS wins on single-core benchmarks. It scores 3626 in PassMark single-thread versus 2742 for the 3900XT, a 24.4% advantage. In Geekbench single-core, the 8840HS scores 1899 against 1640, a 13.6% lead.

Q: How much faster is the 3900XT in multi-core workloads?

A: The 3900XT is dramatically faster. It leads by 111.6% in Cinebench R23 multi-core (27688 vs 13082) and by 36.4% in Cinebench R15 multi-core (2790 vs 2045). In PassMark multithread, it scores 32575 versus 24990, a 30.4% improvement.

Q: Do these CPUs support the same memory types?

A: No. The 3900XT supports DDR4 memory with a dual-channel bus and 51.2 GB/s bandwidth. The 8840HS supports DDR5 memory with a dual-channel bus and 89.6 GB/s bandwidth. The 8840HS has nearly 75% more memory bandwidth.

Q: Which processor has integrated graphics?

A: Only the AMD Ryzen 7 8840HS includes integrated graphics, specifically the Radeon 780M. The AMD Ryzen 9 3900XT has no integrated graphics, meaning it requires a discrete GPU for display output.

Q: What are the core and thread counts?

A: The 3900XT has 12 cores and 24 threads. The 8840HS has 8 cores and 16 threads. This 50% core advantage for the 3900XT drives its multi-threaded benchmark wins.

Q: Which CPU has a higher boost clock?

A: The 8840HS has the higher boost clock at 5.10 GHz, compared to the 3900XT’s 4.70 GHz. The 8840HS also has a lower base clock at 3.30 GHz versus the 3900XT’s 3.90 GHz.

Architecture Differences

The two CPUs come from entirely different eras and design philosophies. The 3900XT is based on Zen 2 architecture, codenamed Matisse 2, built on a 7nm process node from TSMC. It uses a chiplet design with a die size of 2x 74 mm² and 7,600 million transistors. The 8840HS, in contrast, is Zen 4 architecture, codenamed Hawk Point, built on a 4nm process node. It is a monolithic die at 178 mm² with 25,000 million transistors. The transistor density difference is stark: the 8840HS packs over three times the transistors into a single die, enabled by the smaller process node.

Cache hierarchies also diverge significantly. Both have 64 KB of L1 cache per core, but the L2 cache differs: the 3900XT has 512 KB per core, while the 8840HS has 1 MB per core. The L3 cache is where the 3900XT shines, with 64 MB total versus 16 MB shared for the 8840HS. That 4x L3 cache advantage helps the 3900XT in data-heavy workloads, as seen in its 54.4% lead in PassMark data compression.

Memory support is a generational leap. The 3900XT uses DDR4 with 51.2 GB/s bandwidth, while the 8840HS uses DDR5 with 89.6 GB/s bandwidth. The 8840HS also offers more PCIe lanes at 20 (Gen 4) versus the 3900XT’s 24 lanes (Gen 4), though the 3900XT has more total lanes. The socket types are incompatible: AM4 for the 3900XT and FP8 for the 8840HS, reflecting the desktop versus mobile split.

The 8840HS includes the Radeon 780M integrated GPU, a feature absent on the 3900XT. The 3900XT has an unlocked multiplier for overclocking, while the 8840HS is locked. The 8840HS’s 28W TDP versus the 3900XT’s 105W TDP underscores the mobile chip’s efficiency focus. The 8840HS also has a newer release date (December 2023) versus the 3900XT (July 2020).

Specification Differences

| Specification | AMD Ryzen 9 3900XT | AMD Ryzen 7 8840HS |

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

| Cores | 12 | 8 |

| Threads | 24 | 16 |

| Base Clock | 3.90 GHz | 3.30 GHz |

| Boost Clock | 4.70 GHz | 5.10 GHz |

| TDP | 105W | 28W |

| Socket | AMD Socket AM4 | AMD Socket FP8 |

| Architecture | Zen 2 | Zen 4 |

| Process Node | 7 nm | 4 nm |

| Transistors | 7,600 million | 25,000 million |

| Die Size | 2x 74 mm² | 178 mm² |

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

| L3 Cache | 64 MB | 16 MB (shared) |

| Memory Support | DDR4 | DDR5 |

| Memory Bandwidth | 51.2 GB/s | 89.6 GB/s |

| PCIe Lanes | Gen 4, 24 Lanes | Gen 4, 20 Lanes |

| Integrated Graphics | None | Radeon 780M |

| Market Segment | Desktop | Mobile |

| Multiplier Unlocked | Yes | No |

Head-to-Head Benchmarks

The Cinebench tests reveal the 3900XT’s dominance in multi-threaded scenarios. In Cinebench R23 multi-core, the 3900XT scores 27688 against the 8840HS’s 13082, a 111.6% advantage. The R15 multi-core test shows a smaller but still substantial 36.4% lead (2790 vs 2045). These are not marginal wins; they represent the 3900XT’s core and thread advantage being fully utilized. The 8840HS cannot compete in any multi-threaded metric, losing PassMark multithread by 30.4% (32575 vs 24990) and PassMark physics by 54.6% (1776 vs 1149).

The 8840HS fights back in single-thread tests. Its PassMark single-thread score of 3626 beats the 3900XT’s 2742 by 24.4%. Geekbench single-core shows a 13.6% win (1899 vs 1640). Interestingly, the Cinebench single-core tests tell a different story: the 3900XT wins R15 single-core by 45.6% (393 vs 270) and R23 single-core by 125% (3909 vs 1737). This discrepancy suggests the 8840HS’s advantage is workload-specific, not universal across all single-threaded applications.

The 3900XT dominates specialized workloads. PassMark find prime numbers shows a 170.9% lead (214 vs 79), the largest delta in the entire dataset. Data encryption favors the 3900XT by 62.2% (28634 vs 17650), and data compression by 54.4% (452328 vs 292888). Extended instructions see a 38% lead (28586 vs 20714). Floating-point math is closer, with the 3900XT ahead by 11.3% (58513 vs 52582), and integer math is tighter still at 10.3% (99722 vs 90382). Random string sorting goes to the 3900XT by 36.1% (48327 vs 35517).

The average benchmark scores are nearly identical: 33736 for the 3900XT and 33667 for the 8840HS, a 0.2% difference. This is because the 8840HS’s large single-thread wins partially offset the 3900XT’s multi-thread dominance. The 3900XT’s nearest rival is the AMD Ryzen 5 7645HX (0.2% delta), while the 8840HS’s nearest rival is the same chip at 0% delta.

Where Each One Wins

The 3900XT wins in every multi-threaded and data-intensive category. It is the correct choice for video rendering, 3D modeling, software compilation, and scientific computing where Cinebench R23 multi-core performance (27688) is the primary metric. Its 170.9% lead in find prime numbers makes it ideal for mathematical workloads. The 54.4% data compression advantage benefits database management and file archiving. The 62.2% data encryption lead suits security-focused applications. Desktop users with access to a discrete GPU will never miss the lack of integrated graphics, and the unlocked multiplier allows for overclocking headroom.

The 8840HS wins in single-thread responsiveness and mobile efficiency. Its 24.4% PassMark single-thread lead (3626 vs 2742) translates to snappier application launches and better performance in legacy software that uses one core. The 13.6% Geekbench single-core advantage (1899 vs 1640) reinforces this. The 89.6 GB/s memory bandwidth versus 51.2 GB/s helps memory-intensive tasks despite the smaller L3 cache. The Radeon 780M integrated GPU makes it a complete package for a laptop without a discrete graphics card. Its 28W TDP means it can sustain performance in thin chassis where the 105W 3900XT would thermally throttle. The 8840HS is the pick for portable productivity, office work, and light content creation where battery life and mobility are paramount.

The data shows no true winner—only the right tool for the right job. The 3900XT is a desktop powerhouse for heavy compute, and the 8840HS is a mobile efficiency champion for everyday tasks. Both are 84th percentile CPUs, but they achieve that rank through entirely different means.