AMD Ryzen 5 PRO 7645 vs AMD Ryzen 9 7940HS Comparison

Head-to-Head Benchmarks

The recorded data splits these two AMD processors into distinct roles. The Ryzen 9 7940HS wins 10 of the 15 head-to-head benchmarks, while the Ryzen 5 PRO 7645 takes 5. The average benchmark score leans slightly toward the PRO chip: the 7940HS averages 31,593 against the 7645's 32,446, placing both near the top of the database (82nd and 83rd percentiles respectively).

The Ryzen 9 7940HS dominates in raw throughput. Its Passmark multithread score of 30,098 beats the 7645's 25,489 by 18.1%. The gap widens in floating-point math, where the 7940HS posts 62,897 versus 45,202, a 39.1% advantage. Integer math follows a similar pattern: 103,044 against 74,782, or 37.8% ahead. Data encryption shows a 30.7% lead (21,777 vs 16,657), while data compression favors the 7940HS by 27.6% (365,352 vs 286,298). Extended instructions run 26% faster on the 7940HS (27,480 vs 21,813), and random string sorting is 22.7% quicker (42,386 vs 34,557).

Single-thread performance tells a mixed story. The 7940HS wins Passmark single-thread with 3,878 versus 3,652, a 6.2% margin. But Cinebench paints the opposite picture. In Cinebench R23 single-core, the 7645 scores 3,065 against the 7940HS's 1,790, a massive 41.6% advantage. Cinebench R15 single-core also favors the 7645 (308 vs 283, or 8.1% ahead). The 7645 also wins Cinebench R23 multi-core outright: 21,710 versus 16,713, a 23% lead, despite having fewer cores. Cinebench R15 multi-core goes the other way, with the 7940HS ahead at 2,656 versus 2,188 (21.4%). Passmark physics favors the 7645 (1,598 vs 1,450, or 9.3% ahead), and prime number finding is a clear 7645 win: 198 versus 92, a 53.5% margin.

Architecture Differences

Both chips share the Zen 4 architecture, but they are built on different nodes and designed for different sockets. The Ryzen 9 7940HS uses the Phoenix design on a 4 nm TSMC process, while the Ryzen 5 PRO 7645 uses Raphael on a 5 nm TSMC process. Transistor counts diverge sharply: the 7940HS packs 25,000 million transistors on a 178 mm² die, whereas the 7645 has 6,570 million on a 71 mm² die.

Core counts differ as expected from the naming. The 7940HS has 8 cores and 16 threads; the 7645 has 6 cores and 12 threads. Base clocks are close: 4.00 GHz for the 7940HS versus 3.80 GHz for the 7645. Boost clocks are also near: 5.20 GHz versus 5.10 GHz. The 7940HS carries a 35 W TDP, while the 7645 is rated at 65 W.

Cache hierarchies show a notable trade-off. Both have 64 KB of L1 per core and 1 MB of L2 per core. The L3 cache, however, favors the 7645: 32 MB shared, double the 16 MB shared on the 7940HS. This larger L3 likely explains the 7645's strong Cinebench results despite fewer cores.

Memory support is DDR5 for both, with dual-channel buses. Memory bandwidth is higher on the 7940HS at 89.6 GB/s versus 83.2 GB/s. Both support ECC memory. PCIe lanes differ: the 7940HS provides Gen 4 with 20 lanes (CPU only), while the 7645 offers Gen 5 with 24 lanes.

Integrated graphics also diverge. The 7940HS features the Radeon 780M, while the 7645 only lists "Radeon Graphics" without a specific model. Sockets are incompatible: the 7940HS uses AMD Socket FP8, while the 7645 uses AMD Socket AM5. The 7940HS targets the mobile segment, whereas the 7645 is classified as server/workstation. The 7645 has a recorded release date of June 12, 2023; the 7940HS has no release date in the database. Both are active production parts, and neither has an unlocked multiplier. Part numbers differ: the 7940HS lists three variants (100-000000954, 100-000000963, 100-000001128), while the 7645 is 100-000000600.

Where Each One Wins

The Ryzen 9 7940HS is the clear choice for compute-heavy parallel workloads. Its wins in Passmark multithread, floating-point math, integer math, encryption, compression, extended instructions, and random string sorting all point to a processor that excels when many threads can run simultaneously. The 39.1% lead in floating-point math and 37.8% in integer math suggest strong performance for scientific computing, financial modeling, or content rendering. The 30.7% encryption lead and 27.6% compression lead make it suitable for file archiving and security tasks. The 6.2% Passmark single-thread win also gives it a slight edge in everyday responsive tasks.

The Ryzen 5 PRO 7645 has a different set of strengths. Its Cinebench R23 multi-core score is 23% higher than the 7940HS, which is surprising given its 6-core configuration. The 41.6% single-core lead in Cinebench R23 indicates excellent per-thread performance, likely aided by the larger 32 MB L3 cache. The 53.5% advantage in prime number finding and 9.3% lead in physics suggest strong integer and simulation workloads. The 7645's higher TDP (65 W versus 35 W) may allow sustained clock behavior in longer renders, which could explain its Cinebench R23 multi-core dominance.

For mobile users, the 7940HS offers a lower 35 W TDP and a more powerful iGPU (Radeon 780M), making it attractive for thin-and-light laptops with occasional gaming or GPU-accelerated tasks. The 7645, with its server/workstation classification and AM5 socket, fits desktop or workstation builds where power draw is less constrained and PCIe Gen 5 connectivity matters.

FAQ

Q: Which processor has a higher average benchmark score?

A: The Ryzen 5 PRO 7645 averages 32,446, while the Ryzen 9 7940HS averages 31,593. The 7645 sits at the 83rd percentile of all CPUs, one point higher than the 7940HS at the 82nd percentile.

Q: Why does the 6-core Ryzen 5 PRO 7645 beat the 8-core Ryzen 9 7940HS in Cinebench R23 multi-core?

A: The 7645 scores 21,710 in Cinebench R23 multi-core versus 16,713 for the 7940HS, a 23% difference. The 7645 has 32 MB of shared L3 cache, double the 7940HS's 16 MB, and a higher 65 W TDP, which likely allows sustained performance under load.

Q: Which chip has better single-thread performance?

A: It depends on the test. The 7940HS wins Passmark single-thread with 3,878 versus 3,652 (6.2% ahead). The 7645 wins Cinebench R23 single-core by 41.6% (3,065 vs 1,790) and Cinebench R15 single-core by 8.1% (308 vs 283).

Q: What are the memory bandwidth differences?

A: The Ryzen 9 7940HS has a memory bandwidth of 89.6 GB/s, while the Ryzen 5 PRO 7645 has 83.2 GB/s. Both support dual-channel DDR5 and ECC memory.

Q: Which processor supports PCIe Gen 5?

A: Only the Ryzen 5 PRO 7645 supports PCIe Gen 5, with 24 lanes (CPU only). The Ryzen 9 7940HS is limited to PCIe Gen 4 with 20 lanes.

Q: How do the integrated graphics compare?

A: The 7940HS features the Radeon 780M, while the 7645 lists a generic "Radeon Graphics" without a specific model. The 7940HS also has a lower TDP of 35 W versus 65 W for the 7645.

Specification Differences

| Field | AMD Ryzen 9 7940HS | AMD Ryzen 5 PRO 7645 |

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

| Cores | 8 | 6 |

| Threads | 16 | 12 |

| Base Clock | 4.00 GHz | 3.80 GHz |

| Boost Clock | 5.20 GHz | 5.10 GHz |

| TDP | 35 W | 65 W |

| Socket | AMD Socket FP8 | AMD Socket AM5 |

| Codename | Phoenix | Raphael |

| Process Node | 4 nm (TSMC) | 5 nm (TSMC) |

| Transistors | 25,000 million | 6,570 million |

| Die Size | 178 mm² | 71 mm² |

| L3 Cache | 16 MB (shared) | 32 MB (shared) |

| Memory Bandwidth | 89.6 GB/s | 83.2 GB/s |

| PCIe | Gen 4, 20 Lanes (CPU only) | Gen 5, 24 Lanes (CPU only) |

| Integrated Graphics | Radeon 780M | Radeon Graphics |

| Market Segment | Mobile | Server/Workstation |

| Release Date | Not recorded | 2023-06-12 |

| Part Number | 100-000000954, 100-000000963, 100-000001128 | 100-000000600 |

Both processors share the Zen 4 architecture, 64 KB L1 per core, 1 MB L2 per core, DDR5 memory support, dual-channel memory bus, ECC memory support, and a locked multiplier. Both are in the 7000 series and are actively produced by AMD.