AMD EPYC 4585PX vs AMD EPYC 9255 Comparison

The AMD EPYC 9255 and AMD EPYC 4585PX represent two distinct approaches to the same Zen 5 architecture, one aimed at massive multi-threaded throughput in a dual-socket-capable platform, the other at high-frequency responsiveness in a single-socket, mainstream-adjacent design. The recorded data shows a clear split: the EPYC 9255 wins 15 of the 17 head-to-head benchmark comparisons, while the EPYC 4585PX takes the remaining two, which happen to be the most important for lightly-threaded workloads.

Head-to-Head Benchmarks

The EPYC 9255’s advantage is most pronounced in workloads that scale with core count and memory bandwidth. In PassMark’s physics test, the EPYC 9255 scores 9740 against 6612 for the EPYC 4585PX, a 47.3% lead. That is the largest delta in the entire comparison, and it reflects the 9255’s 24 cores versus 16 cores, plus its twelve-channel memory bus. Random string sorting shows a 35.7% gap (129202 versus 95210), a workload heavily dependent on memory latency and bandwidth. Data encryption is another standout: 59668 versus 47224, a 26.4% advantage for the 9255, likely due to the extra cores handling parallel cryptographic operations.

Integer math follows the same pattern. The EPYC 9255 produces 306442 against 248563, a 23.3% win. Floating-point math is close behind at 19.7% (183367 versus 153219). Data compression, a common server workload, favors the 9255 by 15.2% (1018904 versus 884774). The multi-threaded PassMark score, which aggregates many of these sub-tests, lands at 76580 for the 9255 versus 68908 for the 4585PX, an 11.1% margin. Extended instructions show a smaller but still decisive 8.2% gap (75185 versus 69457). Even the Cinebench suite, which often favors higher clock speeds, goes to the 9255 across the board: R15 multi-core 6483 versus 6093, R20 multi-core 27013 versus 25389, and R23 multi-core 64318 versus 60451, each with a consistent 6.4% delta. Single-core Cinebench results also favor the 9255 by 6.4%: R15 single 915 versus 860, R20 single 3813 versus 3584, and R23 single 9080 versus 8534. Find prime numbers, a test sensitive to integer instruction efficiency, shows a 6% edge for the 9255 (580 versus 547).

The EPYC 4585PX’s two wins are in PassMark’s single-threaded metrics, where it scores 4538 against 3655, a 19.5% advantage. That is a substantial victory, and it aligns with the 4585PX’s higher base clock of 4.30 GHz and boost clock of 5.70 GHz, versus the 9255’s 3.25 GHz base and 4.80 GHz boost. In any application that cannot use more than one or two cores, the 4585PX is the faster part. However, the database shows that this advantage does not translate into a win in the Cinebench single-core tests, where the 9255 still leads. The PassMark single-thread test evidently stresses different aspects of the microarchitecture, likely clock speed and memory latency, where the 4585PX’s design shines.

FAQ

Q: Which processor has a higher average benchmark score?

A: The AMD EPYC 9255 has an average benchmark score of 116388, while the AMD EPYC 4585PX scores 99324. The 9255 sits in the 97th percentile of all CPUs, and the 4585PX also sits in the 97th percentile, but the raw average is about 17% higher for the 9255.

Q: How does the EPYC 9255 compare to its nearest rivals?

A: The EPYC 9255’s closest rival is the Intel Xeon 658X, which scores 116060, a 0.3% delta. It is also 1% ahead of the Intel Xeon 6527P (115190), and 1.6% behind the Intel Xeon w7-3565X (118307). The AMD EPYC 9384X leads it by 3.4% (120427).

Q: What are the EPYC 4585PX’s nearest competitors?

A: The AMD Ryzen Threadripper PRO 5965WX is 0.8% behind at 98504, while the AMD Ryzen Threadripper PRO 9955WX leads by 1.7% (101041). The AMD Ryzen 9 9955HX3D is 1.9% behind (97453), and the AMD EPYC 7513 is 2.9% ahead (102244).

Q: Does the EPYC 4585PX have any integrated graphics?

A: Yes, the EPYC 4585PX includes Radeon Graphics, while the EPYC 9255 has no integrated graphics. This is a notable difference for systems that want a display output without a separate GPU.

Q: What is the memory bandwidth difference?

A: The EPYC 9255 uses a twelve-channel memory bus with a bandwidth of 576.0 GB/s. The EPYC 4585PX uses a dual-channel bus with 89.6 GB/s. That is a 6.4x difference in theoretical peak bandwidth, which explains the large gaps in memory-sensitive benchmarks.

Q: Which processor supports more PCIe lanes?

A: The EPYC 9255 provides 128 PCIe Gen 5 lanes (CPU only), whereas the EPYC 4585PX provides 24 PCIe Gen 5 lanes (CPU only). For servers with many NVMe drives, GPUs, or network cards, the 9255 offers far more expansion capacity.

Architecture Differences

Both processors are built on AMD’s Zen 5 architecture at TSMC’s 4 nm process node, but they diverge significantly in die configuration and platform. The EPYC 9255, from the EPYC 9005 series with the codename Turin, uses four chiplets, each 70.6 mm², for a total of 24 cores and 48 threads. The EPYC 4585PX, from the EPYC 4005 series with the codename Grado, uses two chiplets of the same 70.6 mm² size, yielding 16 cores and 32 threads. The transistor counts reflect this: 33,260 million for the 9255 versus 16,630 million for the 4585PX, exactly double.

Cache hierarchies are similar per core: both have 80 KB of L1 per core and 1 MB of L2 per core. The L3 cache is 128 MB on both parts, but the 9255 reports it as shared across its four chiplets, while the 4585PX lists 128 MB without specifying the sharing arrangement. Neither processor uses 3D V-Cache. The sockets are entirely different: the 9255 uses AMD Socket SP5, the server platform, while the 4585PX uses AMD Socket AM5, the mainstream desktop socket. This has profound implications for motherboard choice, memory channels, and overall system cost.

Memory support is DDR5 on both, but the 9255’s twelve-channel bus versus the 4585PX’s dual-channel bus is a fundamental architectural gap. The 9255 provides 576.0 GB/s of bandwidth, while the 4585PX provides 89.6 GB/s. Both support ECC memory. The PCIe configuration also differs sharply: 128 lanes on the 9255 versus 24 lanes on the 4585PX, both Gen 5. The 4585PX integrates Radeon Graphics, while the 9255 has no integrated graphics. The 9255 has a TDP of 200 watts, the 4585PX a TDP of 170 watts, though the 9255’s higher core count and memory controller explain the extra power draw.

The Verdict

The benchmark data indicates that the AMD EPYC 9255 is the superior processor for multi-threaded, data-intensive server workloads. Its wins in data encryption (26.4%), integer math (23.3%), floating-point math (19.7%), and physics (47.3%) show that it is built for throughput. The 128 PCIe lanes and 576.0 GB/s of memory bandwidth make it suitable for dense virtualization, large databases, and high-performance computing clusters. Its average benchmark score of 116388 places it in the 97th percentile, and it trades nearly evenly with the Intel Xeon 658X and Xeon 6527P, while trailing the Xeon w7-3565X by only 1.6%.

The AMD EPYC 4585PX is the choice for single-threaded performance and low-latency response. Its 19.5% lead in PassMark single-thread testing (4538 versus 3655) is decisive, and its boost clock of 5.70 GHz is the highest recorded between the two. The dual-channel memory and 24 PCIe lanes are limiting for server-scale expansion, but the AM5 socket and integrated Radeon Graphics make it a compelling option for a workstation or a compact single-socket server where per-core speed matters more than raw core count. Its average score of 99324 is still in the 97th percentile, and it outperforms the Ryzen Threadripper PRO 5965WX by 0.8% and the Ryzen 9 9955HX3D by 1.9%, though it trails the Ryzen Threadripper PRO 9955WX by 1.7% and the EPYC 7513 by 2.9%.

For a dual-socket capable, high-core-count server, the EPYC 9255 is the clear winner. For a single-socket system optimized for lightly-threaded applications or for a platform that leverages the AM5 ecosystem, the EPYC 4585PX offers the best single-thread results in this comparison.

Specification Differences

| Specification | AMD EPYC 9255 | AMD EPYC 4585PX |

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

| Cores | 24 | 16 |

| Threads | 48 | 32 |

| Base Clock | 3.25 GHz | 4.30 GHz |

| Boost Clock | 4.80 GHz | 5.70 GHz |

| TDP | 200 W | 170 W |

| Socket | AMD Socket SP5 | AMD Socket AM5 |

| Codename | Turin | Grado |

| Transistors | 33,260 million | 16,630 million |

| Die Size | 4x 70.6 mm² | 2x 70.6 mm² |

| Memory Bus | Twelve-channel | Dual-channel |

| Memory Bandwidth | 576.0 GB/s | 89.6 GB/s |

| PCIe | Gen 5, 128 Lanes (CPU only) | Gen 5, 24 Lanes (CPU only) |

| Integrated Graphics | N/A | Radeon Graphics |

| Launch MSRP | $2495 | $699 |

| Release Date | 2024-10-09 | 2025-05-12 |

| Part Number | 100-000000694 | 100-000001561 |