AMD Ryzen 5 PRO 9645 vs AMD Ryzen Threadripper PRO 3955WX Comparison

The AMD Ryzen 5 PRO 9645 and AMD Ryzen Threadripper PRO 3955WX occupy different corners of the AMD lineup. The Ryzen 5 PRO 9645 is a 6-core, 12-thread Granite Ridge part built on a 4 nm process, while the Threadripper PRO 3955WX is a 16-core, 32-thread Castle Peak part on 7 nm. Benchmark results from the database show a clear split: the Ryzen 5 PRO 9645 dominates single-thread workloads, while the Threadripper PRO 3955WX leads in multi-threaded and throughput-oriented tests. Both processors sit at the 92nd percentile of all CPUs, but their average benchmark scores differ: 58,916 for the Ryzen 5 PRO 9645 and 56,555 for the Threadripper PRO 3955WX.

Where Each One Wins

The recorded data separates these two processors into distinct use cases. The Ryzen 5 PRO 9645 wins exactly three of the eleven head-to-head Passmark tests: find prime numbers, single-thread, and the duplicate singlethread entry. That makes it the clear choice for workloads that depend on per-core speed, such as interactive applications, lightly threaded software, and any task where a single core must respond quickly. Its single-thread score of 4,636 is 73% higher than the Threadripper PRO 3955WX's 2,679, a gap that no amount of extra cores can close for latency-sensitive operations.

The Threadripper PRO 3955WX wins the remaining eight tests, covering data compression, data encryption, extended instructions, floating point math, integer math, multithread, physics, and random string sorting. These are all throughput-heavy tasks that scale with core count and memory bandwidth. The Threadripper's 16 cores and 32 threads, combined with an eight-channel DDR4 memory bus delivering 204.8 GB/s, give it a decisive edge in parallel processing. For rendering, scientific simulation, database compression, or encryption workloads, the Threadripper PRO 3955WX is the stronger part. The Ryzen 5 PRO 9645, with its 6 cores and dual-channel DDR5 at 89.6 GB/s, cannot match that level of parallel throughput.

Head-to-Head Benchmarks

The largest win for the Ryzen 5 PRO 9645 is in single-thread performance. It scores 4,636 against 2,679 for the Threadripper PRO 3955WX, a 73% advantage. The only other win for the Ryzen 5 is in find prime numbers, where it scores 235 versus 198, an 18.7% lead. These two victories highlight the Zen 5 architecture's strength in per-core integer and branch-heavy work.

The Threadripper PRO 3955WX's biggest wins come in data encryption and random string sorting. It scores 38,058 in data encryption versus 17,599 for the Ryzen 5, a 53.8% margin. In random string sorting, the Threadripper scores 63,758 against 38,410, a 39.8% lead. Data compression shows a 39.6% advantage (601,738 versus 363,736), and integer math is 29.8% ahead (132,456 versus 93,019). The Threadripper also leads in extended instructions by 23.7% (38,952 versus 29,705), multithread by 21.7% (40,155 versus 31,434), physics by 20.9% (2,460 versus 1,945), and floating point math by 19.6% (77,979 versus 62,720). Across all eleven head-to-head tests, the Threadripper PRO 3955WX wins eight, but the Ryzen 5 PRO 9645's single-thread dominance is the most striking single result.

Architecture Differences

The two CPUs come from different generations and process nodes. The Ryzen 5 PRO 9645 uses the Zen 5 architecture on a 4 nm TSMC process, with 8,315 million transistors on a 70.6 mm² die. The Threadripper PRO 3955WX uses Zen 2 on a 7 nm TSMC process, with 7,600 million transistors spread across two 74 mm² dies. The Ryzen 5 has a per-core L1 cache of 80 KB and L2 of 1 MB, while the Threadripper has 64 KB L1 and 512 KB L2 per core. The L3 cache differs significantly: the Ryzen 5 has 32 MB shared, the Threadripper has 64 MB.

Memory support is a major differentiator. The Ryzen 5 PRO 9645 uses DDR5 with a dual-channel bus and 89.6 GB/s bandwidth. The Threadripper PRO 3955WX uses DDR4 with an eight-channel bus and 204.8 GB/s bandwidth. Both support ECC memory. PCIe connectivity also diverges: the Ryzen 5 offers Gen 5 with 24 lanes, while the Threadripper offers Gen 4 with 128 lanes. The Ryzen 5 includes integrated Radeon Graphics; the Threadripper has no integrated graphics. The Ryzen 5 has a 65 W TDP and fits AMD Socket AM5, while the Threadripper has a 280 W TDP and uses AMD Socket WRX8. The Ryzen 5 was released on 2025-09-15, the Threadripper on 2020-07-13. The Threadripper PRO 3955WX had a launch MSRP of $1149; the Ryzen 5 PRO 9645 has no recorded launch MSRP.

FAQ

Q: Which CPU has more cores and threads?

A: The AMD Ryzen Threadripper PRO 3955WX has 16 cores and 32 threads, while the AMD Ryzen 5 PRO 9645 has 6 cores and 12 threads.

Q: Which CPU has the higher boost clock?

A: The Ryzen 5 PRO 9645 boosts to 5.40 GHz, compared to 4.30 GHz for the Threadripper PRO 3955WX.

Q: Which CPU supports DDR5 memory?

A: The Ryzen 5 PRO 9645 supports DDR5, while the Threadripper PRO 3955WX supports DDR4.

Q: Does either CPU have integrated graphics?

A: The Ryzen 5 PRO 9645 includes Radeon Graphics, but the Threadripper PRO 3955WX does not have integrated graphics.

Q: Which CPU has higher memory bandwidth?

A: The Threadripper PRO 3955WX has 204.8 GB/s of memory bandwidth, versus 89.6 GB/s for the Ryzen 5 PRO 9645.

Q: Which CPU is newer?

A: The Ryzen 5 PRO 9645 was released on 2025-09-15, while the Threadripper PRO 3955WX was released on 2020-07-13.

Specification Differences

| Field | AMD Ryzen 5 PRO 9645 | AMD Ryzen Threadripper PRO 3955WX |

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

| Series | 9000 series | 3000 series |

| Cores | 6 | 16 |

| Threads | 12 | 32 |

| Boost Clock | 5.40 GHz | 4.30 GHz |

| TDP | 65 W | 280 W |

| Socket | AMD Socket AM5 | AMD Socket WRX8 |

| Architecture | Zen 5 (Granite Ridge) | Zen 2 (Castle Peak) |

| Process Node | 4 nm | 7 nm |

| Transistors | 8,315 million | 7,600 million |

| Die Size | 70.6 mm² | 2x 74 mm² |

| L1 Cache (per core) | 80 KB | 64 KB |

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

| L3 Cache | 32 MB shared | 64 MB |

| Memory Support | DDR5 | DDR4 |

| Memory Bus | Dual-channel | Eight-channel |

| Memory Bandwidth | 89.6 GB/s | 204.8 GB/s |

| PCIe | Gen 5, 24 Lanes | Gen 4, 128 Lanes |

| Integrated Graphics | Radeon Graphics | None |

| Market Segment | Server/Workstation | Desktop |

| Release Date | 2025-09-15 | 2020-07-13 |

| Launch MSRP | Not recorded | $1149 |

| Part Number | 100-000001409 | 100-000000167 |

The Verdict

The data points to a clear division of labor. The AMD Ryzen 5 PRO 9645 is the better choice for single-thread performance, with a 73% lead in Passmark single-thread and an 18.7% lead in prime number finding. It also consumes far less power at 65 W TDP, supports DDR5, and includes integrated graphics. Its average benchmark score of 58,916 is higher than the Threadripper's 56,555, despite having only 6 cores. For users who prioritize per-core speed, low power, and a modern platform, the Ryzen 5 PRO 9645 is the stronger option.

The AMD Ryzen Threadripper PRO 3955WX is the clear winner for parallel workloads. It wins eight of eleven head-to-head tests, with the largest margins in data encryption (53.8%), random string sorting (39.8%), and data compression (39.6%). Its 16 cores, 32 threads, 64 MB L3 cache, and 204.8 GB/s memory bandwidth make it the superior part for multi-threaded compute, large data sets, and memory-intensive tasks. The 128 PCIe Gen 4 lanes also provide extensive I/O capability. The trade-off is a 280 W TDP and an older Zen 2 architecture. For workloads that scale with cores and memory, the Threadripper PRO 3955WX is the appropriate pick.