AMD EPYC 4585PX vs AMD Ryzen 9 PRO 9945 Comparison

The AMD EPYC 4585PX and the AMD Ryzen 9 PRO 9945 are both Zen 5-based processors on the AM5 socket, but they target different segments within the server and workstation market. The data reveals a clear performance hierarchy, with the EPYC part dominating in multi-threaded workloads while the Ryzen PRO chip claims a narrow victory in single-threaded tests. This analysis will break down the head-to-head benchmark results, provide a verdict based strictly on the data, and answer common questions about these two processors.

Head-to-Head Benchmarks

The benchmark results show a decisive overall victory for the AMD EPYC 4585PX, winning 9 out of 11 head-to-head comparisons. The most dramatic difference appears in the `passmark_physics` test, where the EPYC 4585PX scores 6612 against the Ryzen 9 PRO 9945's 2902, a staggering 127.8% advantage. This single result highlights the EPYC's substantial lead in a workload that is likely highly parallel and sensitive to core count and cache size.

Beyond physics, the EPYC 4585PX maintains a consistent and significant lead across all other multi-threaded workloads. In `passmark_data_compression`, it scores 884774 versus 579972, a 52.6% delta. The `passmark_data_encryption` test shows a 55.1% advantage (47224 vs 30450), and `passmark_extended_instructions` reveals a 56.5% lead (69457 vs 44374). The pattern continues with `passmark_find_prime_numbers` (547 vs 342, a 59.9% delta) and `passmark_random_string_sorting` (95210 vs 62458, a 52.4% delta).

The gap narrows somewhat in other math-focused benchmarks but remains substantial. In `passmark_integer_math`, the EPYC 4585PX scores 248563 against 171175, a 45.2% difference. Similarly, `passmark_floating_point_math` shows a 42.7% lead (153219 vs 107340). The overall `passmark_multithread` score reinforces this trend: 68908 for the EPYC versus 48664 for the Ryzen, a 41.6% delta. This consistent 40-60% advantage across such a wide range of workloads indicates a fundamental throughput advantage for the EPYC part.

The only area where the AMD Ryzen 9 PRO 9945 emerges victorious is in single-threaded performance. In both `passmark_single_thread` and `passmark_singlethread`, the Ryzen 9 PRO 9945 scores 4619, edging out the EPYC 4585PX's 4538. The delta is -1.8%, a narrow but consistent lead. This suggests that while the EPYC's architecture is optimized for parallel throughput, the Ryzen PRO part has a slight edge in lightly-threaded or latency-sensitive tasks.

The Verdict

The data paints a clear picture: the AMD EPYC 4585PX is the superior choice for any workload that can utilize multiple cores. Its 41.6% lead in the `passmark_multithread` benchmark and its 127.8% advantage in `passmark_physics` make it the definitive option for server and workstation environments where parallel processing is paramount. The 16-core, 32-thread EPYC 4585PX simply outmuscles the 12-core, 24-thread Ryzen 9 PRO 9945 in every multi-threaded test in the data set. For users with rendering, simulation, virtualization, or heavy compilation tasks, the EPYC's performance advantage is decisive and well-documented.

The AMD Ryzen 9 PRO 9945, however, is not without merit. Its narrow 1.8% lead in single-threaded benchmarks indicates it is the better choice for workloads that are primarily single-threaded and require the absolute fastest response time per core. This could include certain legacy applications, specific scripting workloads, or front-end tasks in a development environment. However, this advantage is small, and it comes at the cost of a massive multi-threaded deficit.

Given the performance data, the choice is clear. For a general-purpose server or workstation CPU where the workload mix includes any significant parallel component, the AMD EPYC 4585PX is the recommended part. Its consistent 40-60% performance advantage in the majority of tested workloads is too significant to ignore. The Ryzen 9 PRO 9945 should only be considered if the workload is strictly and exclusively single-threaded, where its 1.8% edge might be relevant, and even then, the trade-off in multi-threaded performance is severe.

FAQ

Q: Which CPU is faster in multi-threaded tasks?

A: The AMD EPYC 4585PX is significantly faster. It leads by 41.6% in the `passmark_multithread` benchmark and by 127.8% in `passmark_physics`, demonstrating a major advantage in parallel workloads.

Q: Does the Ryzen 9 PRO 9945 win any benchmarks?

A: Yes, it wins in single-threaded performance. It scores 4619 in `passmark_single_thread` versus the EPYC's 4538, a 1.8% lead.

Q: How do their overall benchmark scores compare?

A: The EPYC 4585PX has an average benchmark score of 99324, which places it in the 97th percentile of all CPUs. The Ryzen 9 PRO 9945 has an average score of 96083, placing it in the 96th percentile.

Q: Are both processors on the same socket?

A: Yes, both the AMD EPYC 4585PX and the AMD Ryzen 9 PRO 9945 use the AMD Socket AM5.

Q: What is the difference in L3 cache size?

A: The EPYC 4585PX has a 128 MB L3 cache, which is double the 64 MB L3 cache found on the Ryzen 9 PRO 9945.

Q: What is the release date of each processor?

A: The AMD EPYC 4585PX was released on 2025-05-12, while the AMD Ryzen 9 PRO 9945 was released later on 2025-09-15.

Specification Differences

The two processors differ in several key specifications. The AMD EPYC 4585PX has 16 cores and 32 threads, while the AMD Ryzen 9 PRO 9945 has 12 cores and 24 threads. This core count difference is a primary driver of the performance gap. The base clock of the EPYC is 4.30 GHz, compared to 3.40 GHz for the Ryzen PRO. The boost clocks also differ, with the EPYC reaching 5.70 GHz and the Ryzen 9 PRO topping out at 5.40 GHz.

The thermal design power (TDP) is a major differentiator. The EPYC 4585PX has a TDP of 170 watts, while the Ryzen 9 PRO 9945 has a much lower TDP of 65 watts. The L3 cache also differs, with the EPYC featuring 128 MB and the Ryzen 9 PRO having 64 MB. The EPYC's launch MSRP was $699, while the Ryzen 9 PRO's launch MSRP is not available in the data. The part numbers are also different: 100-000001561 for the EPYC and 100-000001407 for the Ryzen PRO.

Architecture Differences

While both processors are built by TSMC on a 4 nm process node and have the same transistor count of 16,630 million and die size of 2x 70.6 mm², they belong to different families. The AMD EPYC 4585PX is from the EPYC 4005 series with the codename "Grado," while the AMD Ryzen 9 PRO 9945 is from the 9000 series with the codename "Granite Ridge." Both are based on the Zen 5 architecture, but their generations are listed as "EPYC (Zen 5 (Grado))" and "Ryzen 9 (Zen 5 (Granite Ridge))" respectively.

The cache hierarchy is identical in structure, with 80 KB of L1 cache per core and 1 MB of L2 cache per core. However, the total L3 cache differs significantly, as noted above. Both processors support DDR5 memory with a dual-channel bus and 89.6 GB/s of memory bandwidth, and both support ECC memory. They also both feature Radeon Graphics integrated and support PCIe Gen 5 with 24 CPU-only lanes. Neither processor has an unlocked multiplier. The market segment for both is listed as "Server/Workstation," and both are currently in active production.