AMD Ryzen 9 5900 vs AMD Ryzen 9 7845HX Comparison

The AMD Ryzen 9 5900 and AMD Ryzen 9 7845HX are both 12-core, 24-thread processors, yet they occupy different worlds: one is a desktop chip from the 5000 series, the other a mobile chip from the 7000 series. The benchmark data reveals a clear split—the 5900 dominates in legacy single-threaded workloads, while the 7845HX sweeps nearly every modern and multi-threaded test. This is not a simple "newer is better" story; it is a tale of architecture, power envelopes, and how synthetic benchmarks can tell conflicting narratives.

Where Each One Wins

The data splits these two CPUs into distinct use-case categories. The AMD Ryzen 9 5900 wins 3 head-to-head benchmarks, all of which are Cinebench tests. Its most dramatic victory is in Cinebench R23 single-core, where it scores 4070 against the 7845HX’s 1852—a 119.8% delta. It also wins Cinebench R15 single-core (410 vs 295, a 39% delta) and Cinebench R23 multi-core (28834 vs 26876, a 7.3% delta). This makes the 5900 the clear choice for applications that rely on older, single-threaded instruction paths or specific Cinebench rendering workloads, particularly the R23 multi-core variant.

The AMD Ryzen 9 7845HX wins 12 of the 15 benchmarks, including every PassMark test and all 3DMark tests (not shown in head-to-head but present in its benchmark list). Its wins are broad: data compression (543539 vs 411453), encryption (32789 vs 26247), extended instructions (41020 vs 26859), prime numbers (329 vs 213), floating-point math (94287 vs 69124), integer math (155118 vs 128641), multithread (45010 vs 33969), physics (2346 vs 1697), random string sorting (63223 vs 43386), and single-thread (3935 vs 3439). In every one of these, the 7845HX leads by margins ranging from 12.6% to 35.3%. For modern productivity, math-heavy simulation, compression, or encryption tasks, the 7845HX is unequivocally the stronger performer.

Architecture Differences

The underlying designs explain the performance split. The Ryzen 9 5900 uses Zen 3 architecture on a 7 nm TSMC process, with a codename of Vermeer. It is built on the AMD Socket AM4 platform for desktops and has a TDP of 65 watts. Its cache layout is 64 KB L1 per core and 512 KB L2 per core, with a 64 MB L3 cache. It supports DDR4 memory in a dual-channel configuration, offering 51.2 GB/s bandwidth. The chip has 8,300 million transistors across a 2x 74 mm² die size. It has no integrated graphics and uses PCIe Gen 4 with 20 lanes.

In contrast, the Ryzen 9 7845HX uses Zen 4 architecture on a 5 nm TSMC process, codenamed Dragon Range. It is a mobile processor on the AMD Socket FL1, with a lower TDP of 55 watts. The cache hierarchy is different: 64 KB L1 per core, but a doubled 1 MB L2 per core, and a 64 MB shared L3. It supports DDR5 memory, also dual-channel, but with a significantly higher 83.2 GB/s bandwidth. The 7845HX packs 13,140 million transistors across a 2x 71 mm² die size. It includes Radeon 610M integrated graphics and uses PCIe Gen 5 with 28 lanes. The smaller process node and doubled L2 cache are likely contributors to its PassMark dominance, while the lower TDP suggests better power efficiency for mobile workloads.

Head-to-Head Benchmarks

The largest win for the Ryzen 9 5900 is in Cinebench R23 single-core, where it scores 4070 versus 1852 for the 7845HX—a 119.8% advantage. This is a staggering gap that suggests the 5900’s higher boost clock of 4.70 GHz (compared to 5.20 GHz for the 7845HX) does not tell the whole story; the 5900’s Zen 3 architecture appears to execute this specific single-threaded workload far more efficiently. Similarly, in Cinebench R15 single-core, the 5900’s 410 beats the 7845HX’s 295 by 39%. In Cinebench R23 multi-core, the 5900 leads by 7.3% (28834 vs 26876), which is surprising given the 7845HX’s superior performance in other multi-threaded tests—this may indicate a Cinebench-specific optimization for the desktop chip.

The 7845HX’s biggest win is in Cinebench R15 multi-core, where it scores 4320 against the 5900’s 2906—a 32.7% delta. This is its largest margin in any benchmark. It also wins PassMark extended instructions by 34.5% (41020 vs 26859), find prime numbers by 35.3% (329 vs 213), and random string sorting by 31.4% (63223 vs 43386). In data compression, it leads by 24.3% (543539 vs 411453), and in floating-point math by 26.7% (94287 vs 69124). The 7845HX’s PassMark single-thread score of 3935 beats the 5900’s 3439 by 12.6%, showing that its architecture is faster even in single-threaded contexts outside of Cinebench. The overall average benchmark scores are close—46971 for the 5900 and 46654 for the 7845HX—with the 5900 leading by just 0.7%, but the distribution of wins is heavily skewed.

The Verdict

The data suggests a clear choice based on workload. If your primary benchmark is Cinebench R23 multi-core, the Ryzen 9 5900 is the better pick, offering a 7.3% advantage. It also wins the legacy Cinebench R15 single-core test by 39%, making it suitable for older software that relies on that specific performance path. For a desktop user with DDR4 memory and a Socket AM4 motherboard, the 5900 is the logical upgrade, as it also has a 65W TDP and a 4.70 GHz boost clock.

However, for virtually every other measured task, the Ryzen 9 7845HX is superior. It wins 12 of 15 head-to-head benchmarks, with margins from 12.6% to 35.3% in PassMark tests. Its higher boost clock of 5.20 GHz, doubled L2 cache, DDR5 support with 83.2 GB/s bandwidth, and PCIe Gen 5 lanes make it the more capable processor for modern applications. The 7845HX also includes Radeon 610M integrated graphics, which the 5900 lacks entirely. The 7845HX is the better choice for mobile users or those who prioritize encryption, compression, math operations, and general multi-threaded performance. The 5900’s only other advantage is its 89th percentile ranking versus the 7845HX’s 89th percentile—they are statistically tied in overall standing.

FAQ

Q: Which processor has a higher boost clock?

A: The AMD Ryzen 9 7845HX has a boost clock of 5.20 GHz, while the AMD Ryzen 9 5900 has a boost clock of 4.70 GHz.

Q: Which CPU wins in Cinebench R23 single-core performance?

A: The AMD Ryzen 9 5900 wins Cinebench R23 single-core with a score of 4070, which is 119.8% higher than the 7845HX’s 1852.

Q: Does the Ryzen 9 7845HX have integrated graphics?

A: Yes, the Ryzen 9 7845HX includes Radeon 610M integrated graphics, while the Ryzen 9 5900 has no integrated graphics.

Q: Which processor supports faster memory?

A: The Ryzen 9 7845HX supports DDR5 memory with 83.2 GB/s bandwidth, whereas the Ryzen 9 5900 supports DDR4 with 51.2 GB/s bandwidth.

Q: What is the TDP difference between the two?

A: The Ryzen 9 5900 has a TDP of 65 watts, while the Ryzen 9 7845HX has a TDP of 55 watts.

Q: Which chip has more L2 cache per core?

A: The Ryzen 9 7845HX has 1 MB of L2 cache per core, double the 512 KB per core found in the Ryzen 9 5900.

Specification Differences

| Specification | AMD Ryzen 9 5900 | AMD Ryzen 9 7845HX |

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

| Series | 5000 series | 7000 series |

| Base Clock | 3.00 GHz | 3.00 GHz |

| Boost Clock | 4.70 GHz | 5.20 GHz |

| TDP | 65 W | 55 W |

| Socket | AMD Socket AM4 | AMD Socket FL1 |

| Architecture | Zen 3 | Zen 4 |

| Codename | Vermeer | Dragon Range |

| Process Node | 7 nm | 5 nm |

| Transistors | 8,300 million | 13,140 million |

| Die Size | 2x 74 mm² | 2x 71 mm² |

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

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

| Memory Support | DDR4 | DDR5 |

| Memory Bandwidth | 51.2 GB/s | 83.2 GB/s |

| PCIe | Gen 4, 20 Lanes | Gen 5, 28 Lanes |

| Integrated Graphics | None | Radeon 610M |

| Market Segment | Desktop | Mobile |

| Release Date | 2021-01-11 | 2023-01-03 |

| Part Number | 100-000000062 | 100-000000871 |